Why do stars twinkle?

I have always had a pretty good idea why stars twinkle and planets emit a solid beam of light, but I wanted to know the specifics. So, here is a general overview. Enjoy the simplicity.

Stars twinkle because of out atmosphere distorting their image from Earth. Furthermore, as the gases that make up our atmosphere churn, the light from the stars fluctuates and moves slightly resulting in a twinkle. The lights from the stars that we see are not the finite edges of the stars surface but are the light that the stars emit that is obscured by the vast distances and space particles that lie between us and the stars. Obviously, this is why the best images of the stars are taken by telescopes in space.

So, why are planets easy to identify from stars? Man, that is simple. The finite, unwavering image that a planet emits is able to "average out" the turbulent effects of the atmosphere and produce a solid beam of light that appears more stable than that of the stars.

Reference: http://curious.astro.cornell.edu/question.php?number=114

Mikey Pannier Blog

Fabio Carvalho
Observing Jupiter in May
Jupiter rises well after midnight in early May. At A.M. local daylight time on the 1st, it stands just 7° above the southeastern horizon. By May 31, the situation has improved considerably, with Jupiter 22° high at the same hour. Jupiter lies just east of the familiar "handle" of the Teapot asterism in Sagittarius. The best time to view Jupiter through a telescope comes in the hour before dawn, when the region lies highest in the sky. The planet's disk grows from 41" to 44" across this month, just a little shy of the 47" it will reach at maximum in July.Dark features in the jovian atmosphere show up easily. If this is your first time viewing the giant planet, however, expect the features to be subtle. The dark north and south equatorial belts typically come into view first, but smaller features start to appear with patient viewing. Take your time, and wait for moments when Earth's atmosphere steadies - what astronomers call "good seeing." These periods tend to be fleeting, but they're worth the wait.Just as obvious to any Jupiter viewer are its four moons. Each glows bright enough to show up in the smallest telescope, even at low magnification. These moons — Io, Europa, Ganymede, and Callisto — wander around Jupiter with their orbits edge-on to our view. Their back-and-forth motions carry each one in front of and behind the great planet. Watching the moons disappear behind the planet, or their shadows transit the giant globe, ranks among the top solar system sights.Fabio Carvalho imaged the planet from Centro de Estudos do Universo in Brotas, Brazil, April 24, 2008.

Examining the Throat of a Black-Hole Jet

Black-hole jets are among the most violent, and important, phenomena in the universe. When matter falls toward a black hole, it often forms an extremely hot "accretion disk" around the hole as it spirals in. Somehow, despite the intense gravity hauling things inward, the inner part of the accretion disk often manages to emit narrow jets of matter from its top and bottom faces. Typically, a few percent of the infalling stuff ends up getting expelled this way, powered somehow by the energy of the rest falling in.

These accretion-disk jets can extend millions of light-years from the cores of active radio galaxies and quasars. We also see them in miniature squirting from "microquasars" in our own galaxy, when enough matter feeds into a stellar-mass black hole.

Full article here: http://www.skyandtelescope.com/news/18370199.html

-Ryan

Ultra-dense Galaxies Found in Early Universe

ScienceDaily (Apr. 29, 2008) — A team of astronomers looking at the universe's distant past found nine young, unusually compact galaxies, each weighing in at 200 billion times the mass of the Sun. These young galaxies are the equivalent of a human baby that is 20 inches long, yet weighs 180 pounds.

see full article at http://www.sciencedaily.com/releases/2008/04/080429095054.htm

Scars on Mars suggest recent glaciers

Orbiter images show that planet may have gone through many ice ages
A vanished glacier with a mysterious calling card suggests Mars went through many ice ages in its very recent past.
A fresh look at images from the Mars Reconnaissance Orbiter indicates thick glaciers may have existed in the past 100 million years in the planet's equatorial region, but vanished after planetary wobbles changed the climate in certain areas.
"We've gone from seeing Mars as a dead planet for three-plus billion years to one that has been alive in recent times," said Jay Dickson, a geologist at Brown University and lead author of the study. "[The finding] has changed our perspective from a planet that has been dry and dead to one that is icy and active."
Strange flowDickson and other researchers looked at a dead-ended box canyon that slopes down into a larger valley, and discovered glacial deposits of rocks marking a glacier's advance heading upslope into the canyon — something which seems physically impossible.
Here's how it happened, according to the team's calculations: An ice pack at least .62 miles (1 kilometer) thick filled the larger valley to a height exceeding that of the box canyon walls. Glacial ice flowed in the larger valley upstream of the box canyon. So when the glacier reached the box canyon, the ice actually pushed uphill into it.
When the glacier ice retreated, it left behind the mystery of the box canyon and a freshly-paved surface that suggests a recent event.
"We don't see many craters on the glacial deposits," Dickson told SPACE.com. "That's a yardstick we can use for measuring geological age."
Craters on Mars, caused by meteor impacts, remain for hundreds of millions of years, and their prevalence in an area can, like a wrinkled face, indicate an old surface. Newer surfaces lack the multitudes of scars.
Multiple episodesThe finding further suggests that Mars has endured repeated periods of glacial activity instead of just one single event, Dickson said, whose new work on this topic is detailed in the May issue of the journal Geology.
Click for related content
NASA: Mars rovers spared budget cutsNASA captures dynamic Martian avalancheBlack hole captured in mid-belch
The past presence of glaciers could also spark further debate about whether water flowed recently on Mars, given that pressure from the weight of glaciers can melt ice. However, no direct evidence of recent flowing water has been found.
"We don't yet see evidence for melt water at this location, but the fact that there was so much ice here expands our understanding of how active Mars climate has been," said Dickson.

EU to launch second satellite for Galileo

Navigation system designed to rival the American GPS system
BRUSSELS, Belgium - The European Union on Sunday is to launch the second satellite in its much-delayed Galileo navigation system designed to rival the American GPS system.
The experimental satellite will be fired into space on a Russian Soyuz rocket from the Baikonur cosmodrome in Kazakhstan in the early hours of Sunday morning.
Named Giove-B, the satellite will test technologies to be used in the Galileo system including an atomic clock that the EU says will be the most accurate in space.
Touted as technologically superior to GPS, Galileo is scheduled to be operational by 2013 but has encountered delays. Its first satellite was launched in 2005, but the second missed its late 2006 launch due to a short-circuit problem in final testing.
Senior EU officials will monitor the launch of Giove-B from the Fucino control center in central Italy.
Late last year, European Union governments had to agree to a taxpayer bailout after a consortium of private companies from France, Germany, Spain, Britain and Italy walked away from the project in a financing dispute.
The cost of setting up the final network of 20 satellites is expected to be euro3.4 billion (US$5.3 billion). At least euro1 billion (US$1.56 billion) of taxpayers' money has already been spent on it.
Galileo promises to more than double existing GPS coverage, providing navigation for motorists, sailors, pilots and emergency rescue teams. It would improve coverage in high-latitude areas such as northern Europe, and in big cities where skyscrapers can block signals.

Physicists Renew Claim, in New Experiment, of Detecting Dark Matter Particles

A team of Italian and Chinese physicists on Wednesday renewed a controversial claim that they had detected the mysterious dark matter particles that astronomers say swaddle the galaxies in halos and direct the evolution of the universe. The team, called Dama, from “DArk MAtter,” and led by Rita Bernabei of the University of Rome, has maintained since 2000 that a yearly modulation in the rate of flashes in a detector nearly a mile underneath the Gran Sasso mountain in Italy is the result of the Earth’s passage through a “wind” of dark matter particles as it goes around the Sun. Other groups of hunters of dark matter have just as consistently failed to find any evidence of the putative particles. At a meeting in Venice, Dr. Bernabei reported that a new, bigger experiment named Dama/Libra had now observed the same modulation. “No other experiment whose result can be directly compared in a model-independent way is available so far,” she said. The findings increase the chances that the modulation is real, outside dark matter experts say. Dark matter has taunted astronomers and physicists ever since the astronomer Fritz Zwicky of the California Institute of Technology pointed out in the 1930s that clusters of galaxies appear to be missing enough visible matter to hold them together gravitationally. Speculation has centered on the possibility that the dark matter consists of hypothetical elementary particles left over from the Big Bang — so-called WIMPs, or weakly interacting massive particles, that are immune to most forces of nature and so can pass through us and the Earth like ghosts. The Dama team uses sodium iodide, which flashes light when a WIMP smashes into it, as a detector. The first experiment, which ran from 1996 to 2002, had 220 pounds of sodium iodide; the second — which began in 2003 — 500 pounds. In both cases, Dr. Bernabei and her colleagues found that the rate of flashes was highest in June and lowest in December. Loud skepticism by the rest of the dark matter community about Dama’s claims in 2000 led to hard feelings, apparent on the group’s Web site, people.roma2.infn.it/dama/web/home.html Bernard Sadoulet, a rival dark matter hunter of the University of California, Berkeley, who was present at the conference, said of the new results, “The tension between the measurements of this group and the rest of the community is increasing.” He added that it would take time to digest Dama’s results. Juan Collar of the University of Chicago, a member of another dark matter hunting team, said people were excited about the new results. “You wouldn’t put your hand on fire that this is wimps,” he said, but agreed that some kinds of WIMPs were still among many possibilities, including that the experiment was in error. He said that it would take a lot of evidence from many different directions to crack the dark matter problem. When it is done, “We will see it was the work of a lot of people striking gold,” he said, adding, “It is very tricky, what we are trying to do.”

Video Tour of Arizona Sky Village

Check out this video of a tour of the Arizona Sky Village.
Senior Editor Michael Bakich takes you on a tour of a stargazer's paradise in the American Southwest.

http://www.astronomy.com/asy/default.aspx?c=a&id=6880

Mars Photos Appear to Show Dry Hot Springs

SANTA CLARA, Calif. -- The long and frustrating search for signs of past or present life on Mars took a hopeful turn this month when scientists said they had spotted what they believe are remains of two hot springs -- the kind of warm, protected environments where many scientists think primitive life can thrive.

The researchers said water is not flowing now at the sites, but photographs suggest that it may well have bubbled out of the ground in the relatively recent past -- in planetary terms -- meaning tens of millions, rather than billions, of years ago.

"This is the first time that features that are so close in all of their shapes and details to springs on Earth have been reported and identified on Mars," said Carlton Allen of NASA's Johnson Space Center, who is studying the planet to find interesting landing places for future missions. "This puts the story of water on the Martian surface in a totally different context."

Full Story Here:
http://www.washingtonpost.com/wp-dyn/content/article/2008/04/27/AR2008042701524.html?g=1

-Ryan

Secrets of Massive Black Hole Unveiled

At the cores of many galaxies, supermassive black holes expel powerful jets of particles at nearly the speed of light. Just how they perform this feat has long been one of the mysteries of astrophysics. The leading theory says the particles are accelerated by tightly-twisted magnetic fields close to the black hole, but confirming that idea required an elusive close-up view of the jet's inner throat. Now, using the unrivaled resolution of the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA), astronomers have watched material winding a corkscrew outward path and behaving exactly as predicted by the theory.

Full article: http://www.sciencedaily.com/releases/2008/04/080423131621.htm

Drifting Star Discovered: Implications For Star And Planet Formation Theory

ScienceDaily (Apr. 17, 2008) — By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way.

Full Article: http://www.sciencedaily.com/releases/2008/04/080415101016.htm

Lawmakers Tackle NASA Job Losses

Lawmakers will be in Brevard County this week to talk about the expected job losses at NASA.

The space agency has announced thousands of job losses as they move forward with the Orion space fleet.

Senator Bill Nelson and Congressmen Dave Weldon and Tom Feeney will attend the County Commission Space Workshop aimed at easing the pain caused by job losses.

Glaciers Reveal Martian Climate Has Been Recently Active

ScienceDaily (Apr. 23, 2008) — The prevailing thinking is that Mars is a planet whose active climate has been confined to the distant past. About 3.5 billion years ago, the Red Planet had extensive flowing water and then fell quiet - deadly quiet. It didn't seem the climate had changed much since.

For Full Article: http://www.sciencedaily.com/releases/2008/04/080423131602.htm

Hubble's Colliding Galazy Show: Stunning, beautiful, and wild

Hubble has found some of the most fantastic sights you could wish to see for their 18th anniversary of launch. The colliding galaxies are dancers on the wing, symphonies in space. With some of these pictures, you can practically feel it.The colliding galaxies are part of a fascinating picture of cosmic evolution, and thankfully they're sights where wonder will always beat description.

Our local stellar group used to be an independent small galaxy.

That’s why we rotate in the opposite direction to the rest of the galaxy.

Well, that and our lousy sense of direction… "How to park a stellar cluster", eh?

In about 2 billion years, the Milky Way and Andromeda will merge. The result will be a giant galaxy, and quite a sight for the inhabitants for thousands of generations.

So can we try to get this parking thing right by then?

The spiral galaxies seem to come up with the most dramatic effects, but the little guys with the curved arms doing the dances are just plain elegant.


to see the pictures:

http://www.dailyastronomy.com/story.asp?ID=282712&Title=Hubble’s%20Colliding%20Galaxy%20Show:%20Stunning,%20beautiful,%20and%20wild

Galaxies Gone Wild: Dramatic Collisions Trigger Bursts Of Star Formation

ScienceDaily (Apr. 27, 2008) — Interacting galaxies are found throughout the Universe, sometimes as dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that result in new galaxies. A series of 59 new images of colliding galaxies has been released from the several terabytes of archived raw images from the NASA/ESA Hubble Space Telescope to mark the 18th anniversary of the telescope's launch. This is the largest collection of Hubble images ever released to the public simultaneously.

More?
http://www.sciencedaily.com/releases/2008/04/080424092756.htm

Mars Photos Appear to Show Dry Hot Springs

SANTA CLARA, Calif. -- The long and frustrating search for signs of past or present life on Mars took a hopeful turn this month when scientists said they had spotted what they believe are remains of two hot springs -- the kind of warm, protected environments where many scientists think primitive life can thrive.

for more click here:

http://www.dailyastronomy.com/story.asp?ID=282783&Title=Mars%20Photos%20Appear%20to%20Show%20Dry%20Hot%20Springs

Electric Sail Prototype

Space.com has revealed the introduction of an electric sail prototype that uses the solar wind in order to propel itself through space. This electrically charged solar sail does not need gas or other means of propellant. The "small" prototype has 5-mile long tethers that are positively charged. These electric sails need nothing but the solar wind to move the small craft. Solar panels on the craft should charge the particles on the sails. The solar wind should push against these sails with a similar charge.

The craft would be designed to gather the composition of interstellar gases and dust that make up contents of unexplored space. The first trial of this ship should be in the next three years. The scientists testing this new technology plan to keep the sails in a high Earth orbit that would still allow them to test the forces on the object from the Sun's solar wind.

Additionally, the researches hope to test a "turbo" setting for the sails that would involve the use of radio-frequency waves to increase the speeds. Although this technology will not help us with the expensive and energy inefficient means of propelling the missions into space, it should allow us to explore deeper into regions of the universe.

For images and more, check out: http://www.space.com/businesstechnology/080423-tw-finnish-solar-sail.html

Polarized Aurora

"An international team of scientists has detected that some of the glow of Earth's aurora is polarized, an unexpected state for such emissions. Measurements of this newfound polarization in the Northern Lights may provide scientists with fresh insights into the composition of Earth's upper atmosphere, the configuration of its magnetic field, and the energies of particles from the Sun, the researchers say." - Astronomy.com

Does this interest you professor? Link

Mars Rover's Robotic Arm Glitches Out....again

The Mars Rover has been experiencing a glitch in the motor since 2005, which restricted its ability to move sideways. However, on April 14th the motor glitched sooner than expected, which has NASA sitting in fear for they may not be able to use the Rover's robotic arm for "contact science" if the glitch gets any worse. Read it here.

Sports....In Space?!

A recent article published on Space.com outlines what astronauts apparantly do in there free time in space: come up with new ways to compete! There are a few really interesting ideas, including water ball riding! Read here if you're interested!

When Galaxies Collide...

Scientists released pictures of merging galaxies today to celebrate the 18th anniversary of the Hubble telescope launch. This collection of images is the largest collection ever released to date.
Colliding galaxies are thought to be a key factor in cosmic evolution although they were more common in the early years of the universe than today. In the most active central period of a galaxy interaction, high levels of infrared and far-infrared radiation are common.

http://www.astronomy.com/asy/default.aspx?c=a&id=6862

Galaxies gone Wild

Galaxies gone wild

To mark the 18th anniversary of Hubble's launch, scientists have released 59 images of galaxies merging.

Provided by Hubble Europe

Interacting galaxies are found throughout the universe, sometimes as dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that result in new galaxies. This collection shows 12 of the most dynamic images of the overall 59. NASA, ESA, Hubble Heritage Team (STScI/AURA)-ESA and A. Evans/NRAO, K. Noll, and J. Westphal [View Larger Image]

April 24, 2008
Fifty-nine new images of colliding galaxies make up the largest collection of Hubble images ever released together. As this astonishing Hubble atlas of interacting galaxies illustrates, galaxy collisions produce a remarkable variety of intricate structures.

Interacting galaxies are found throughout the universe, sometimes as dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that result in new galaxies. A series of 59 new images of colliding galaxies has been released from the several terabytes of archived raw images from the NASA/ESA Hubble Space Telescope to mark the 18th anniversary of the telescope's launch. This is the largest collection of Hubble images ever released to the public simultaneously.

Galaxy mergers, which were more common in the early universe than they are today, are thought to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths. Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.

Our own Milky Way contains the debris of the many smaller galaxies it has encountered and devoured in the past, and it is currently absorbing the Sagittarius dwarf elliptical galaxy. In turn, it looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy, resulting in an elliptical galaxy, dubbed "Milkomeda", the new home for the Earth, the Sun and the rest of the Solar System in about two billion years time. The two galaxies are currently rushing towards each other at approximately 500,000 kilometres per hour.

Cutting-edge observations and sophisticated computer models, such as those pioneered by the two Estonian brothers Alar Toomre and Juri Toomre in the 1970s, demonstrate that galaxy collisions are far more common than previously thought. Interactions are slow stately affairs, despite the typically high relative speeds of the interacting galaxies, taking hundreds of millions of years to complete. The interactions usually follow the same progression, and are driven by the tidal pull of gravity. Actual collisions between stars are rare as so much of a galaxy is simply empty space, but as the gravitational webs linking the stars in each galaxy begin to mesh, strong tidal effects disrupt and distort the old patterns leading to new structures, and finally to a new stable configuration.

The pull of the Moon that produces the twice-daily rise and fall of the Earth's oceans illustrates the nature of tidal interactions. Tides between galaxies are much more disruptive than oceanic tides for two main reasons. Firstly, stars in galaxies, unlike the matter that makes up the Earth, are bound together only by the force of gravity. Secondly, galaxies can pass much closer to each other, relative to their size, than do the Earth and the Moon. The billions of stars in each interacting galaxy move individually, following the pull of gravity from all the other stars, so the interwoven tidal forces can produce the most intricate and varied effects as galaxies pass close to each other.

Typically the first tentative sign of an interaction will be a bridge of matter as the first gentle tugs of gravity tease out dust and gas from the approaching galaxies (IC 2810). As the outer reaches of the galaxies begin to intermingle, long streamers of gas and dust, known as tidal tails, stretch out and sweep back to wrap around the cores (NGC 6786, UCG 335, NGC 6050). These long, often spectacular, tidal tails are the signature of an interaction and can persist long after the main action is over. As the galaxy cores approach each other their gas and dust clouds are buffeted and accelerated dramatically by the conflicting pull of matter from all directions (NGC 6621, NGC 5256). These forces can result in shockwaves rippling through the interstellar clouds (ARP 148).

Gas and dust are siphoned into the active central regions, fuelling bursts of star formation that appear as characteristic blue knots of young stars (NGC 454). As the clouds of dust build they are heated so that they radiate strongly, becoming some of the brightest (luminous and ultraluminous) infrared objects (APG 220) in the sky.

These objects emit up to several thousand billion times the luminosity of our Sun. They are the most rapidly star-forming galaxies in today's universe and are linked to the occurrence of quasars. Unlike standard spiral galaxies like the Milky Way, which radiate from stars and hot gas distributed over their entire span of perhaps 100 000 light-years, the energy in luminous and ultraluminous infrared galaxies is primarily generated within their central portion, over an extent of 1000 to 10,000 light-years. This energy emanates both from vigorous star formation processes, which can generate up to a few hundred solar masses of new stars per year (in comparison, the Milky Way generates a few solar masses of new stars per year), and from massive accreting black holes, a million to a billion times the mass of the Sun, in the central region.

Intense star formation regions and high levels of infrared and far- infrared radiation are typical of the most active central period of the interaction and are seen in many of the objects in this release. Other visible signs of an interaction are disruptions to the galaxy nuclei (NGC 3256, NGC 17). This disruption may persist long after the interaction is over, both for the case where a larger galaxy has swallowed a much smaller companion and where two more closely matched galaxies have finally separated.

Most of the 59 new Hubble images are part of a large investigation of luminous and ultraluminous infrared galaxies called the GOALS project (Great Observatories All-sky LIRG Survey). This survey combines observations from Hubble, the NASA Spitzer Space Observatory, the NASA Chandra X-Ray Observatory and NASA Galaxy Explorer. The Hubble observations are led by Professor Aaron S. Evans from the University of Virginia and the National Radio Astronomy Observatory (USA).

A number of the interacting galaxies seen here are included in the The Atlas of Peculiar Galaxies, a remarkable catalog produced by the astronomer Halton Arp in the mid-1960s that built on work by B.A. Vorontsov-Velyaminov from 1959. Arp compiled the catalogue in a pioneering attempt to solve the mystery of the bizarre shapes of galaxies observed by ground-based telescopes. Today, the peculiar structures seen by Arp and others are well understood as the result of complex gravitational interactions.

Pic of the day!!!

2008 April 24

Cygnus Without Stars
Credit & Copyright: Igor Chekalin

Explanation: The sky is full of hydrogen, though it can take a sensitive camera and telescope to see it. For example, this twelve-degree-wide view of the northern part of the constellation Cygnus reveals cosmic clouds of hydrogen gas along the plane of our Milky Way galaxy. The mosaic of telescopic images was recorded through an h-alpha filter that transmits only visible red light from glowing hydrogen atoms. Further digital processing has removed most of what is left of the myriad, point-like Milky Way stars from the scene, though bright Deneb, alpha star of Cygnus and head of the Northern Cross, remains near top center. Recognizable bright nebulae include NGC 7000 (North America Nebula), and IC 5070 (Pelican Nebula) at the upper left with IC 1318 (Butterfly Nebula) and NGC 6888 (Crescent Nebula) at lower right -- but others can be found throughout the wide field. Want the stars back? Just slide your cursor over the picture.

Colliding Galaxies

The Hubble Space Telescope has taken a series of 59 new photos of galaxies colliding, which were realeased today on the 18th anniversary of its launch.

These images provide a window into the aftermath of galaxy collisions, which are much more common than might be thought.

The full article is available at http://www.msnbc.msn.com/id/24282959/?GT1=43001

Radio telescopes capture black hole mid-belch

CHICAGO (Reuters) - Using powerful radio telescopes, scientists have captured a supermassive black hole just as it was belching out a jet of supercharged particles, offering a first look at how these cosmic jets are formed, they said on Wednesday.

Supermassive black holes form the core of many galaxies and astronomers have long believed they were responsible for ejecting jets of particles at nearly the speed of light.

But just how they did it had remained a mystery.

An international team of researchers led by Alan Marscher of Boston University just got its first peek.

Marscher's team aimed the National Radio Astronomy Observatory's Very Long Baseline Array -- a system of 10 radio telescopes -- at the galaxy BL Lacertae.

A kind of supermassive black hole known as a blazar was suspected of spewing out a pair of forceful streams of plasma some 950 million light years from Earth.

A light year, the distance light travels in a year, is about 6 trillion miles.

What they saw was a close up of this charged material winding in corkscrew fashion out of the supermassive black hole, behaving just as astronomers had predicted.

Full story here: http://uk.reuters.com/article/scienceNews/idUKN2338757920080423?sp=true

-Ryan

Losing Our Arctic Ice

Losing our Arctic ice
New research finds that the ice is more vulnerable to sunny weather.
Provided by the American Geophysical Union

"A single unusually clear summer can now have a dramatic impact," says Jennifer Kay. NASA/JPL/Northwestern University
April 22, 2008
The shrinking expanse of Arctic sea ice is increasingly vulnerable to summer sunshine. Unusually sunny weather contributed to last summer's record loss of Arctic ice, while similar weather conditions in past summers did not appear to have comparable impacts, new research concludes.

"The relative importance of solar radiation in the summer is changing," says Jennifer Kay of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, who is lead author of the study. "The amount of sunshine reaching the Arctic is increasingly influential, as there is less ice to reflect it back into space," she says.

The findings by Kay and colleagues at NCAR and Colorado State University (CSU) in Fort Collins indicate that the presence or absence of clouds now has greater implications for sea ice loss.

"A single unusually clear summer can now have a dramatic impact," Kay says.

A report on the new results will be published April 22, 2008 in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

Last summer's loss of Arctic sea ice set a modern-day record, with the ice extent shrinking in September to a minimum of about 4.1 million square kilometers (1.6 million square miles). That was 43 percent less ice coverage than in 1979, when accurate satellite observations began.

The study draws on observations from new NASA satellite radar and lidar instruments. Lidar devices make measurements using lasers. Looking at the first 2 years of satellite data from those sensors, Kay and her colleagues found that total 2007 summertime cloud cover was 16 percent less than the year before, largely because of a strong high-pressure system centered north of Alaska that kept skies clear.

Over a 3-month period in the summer, the increased sunshine was strong enough to melt about a foot of surface ice. Over open water, it was sufficient to increase sea-surface temperatures by 2.4° C (4.3° F). Warmer ocean waters can contribute to sea ice loss by melting the ice from the bottom, thereby thinning it and making it more susceptible to future melt.

"Satellite radar and lidar measurements allow us to observe Arctic clouds in a new way," says CSU's Tristan L'Ecuyer, a co-author of the study. "These new instruments not only provide a very precise view of where clouds exist but also tell us their height and thickness, which are key properties that determine the amount of sunlight clouds reflect back to space."

The research team also examined longer-term records of Arctic cloud and weather patterns, including a 62-year-long record of cloudiness from surface observations at Barrow, Alaska. The scientists found that the 2007 weather and cloud pattern was unusual but not unprecedented. Five other years — 1968, 1971, 1976, 1977, and 1991 — appeared to have lower summertime cloud cover than 2007, but without the same impact on sea ice.

"In a warmer world, the thinner sea ice is becoming increasingly sensitive to year-to-year variations in weather and cloud patterns," Kay says.

The research suggests that warmth from the Sun will increasingly affect Arctic climate in the summer. As the ice shrinks, incoming sunshine triggers a feedback mechanism: the newly exposed dark ocean waters, much darker than the ice, absorb the Sun's radiation instead of reflecting it. This warms the water and melts more ice, which in turn leads to more absorption of radiation and still more warming.

The authors note that, in addition to solar radiation, other factors such as changes in wind patterns and, possibly, shifts in ocean circulation patterns also influence sea ice loss. In particular, strong winds along regions of sea ice retreat were important to last year's loss of ice. The relative importance of these factors, and the precise extent to which global climate change is driving them, are not yet known.

http://www.astronomy.com/asy/default.aspx?c=a&id=6858

Bears Eat Beets.

Artist's conception of region near supermassive black hole where twisted magnetic fields propel and shape jet of particles. (Credit: Marscher et al., Wolfgang Steffen, Cosmovision, NRAO/AUI/NSF)

At the cores of many galaxies, supermassive black holes expel powerful jets of particles at nearly the speed of light. Just how they perform this feat has long been one of the mysteries of astrophysics. The leading theory says the particles are accelerated by tightly-twisted magnetic fields close to the black hole, but confirming that idea required an elusive close-up view of the jet's inner throat. Now, using the unrivaled resolution of the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA), astronomers have watched material winding a corkscrew outward path and behaving exactly as predicted by the theory."We have gotten the clearest look yet at the innermost portion of the jet, where the particles actually are accelerated, and everything we see supports the idea that twisted, coiled magnetic fields are propelling the material outward," said Alan Marscher, of Boston University, leader of an international research team. "This is a major advance in our understanding of a remarkable process that occurs throughout the Universe," he added.

Nice weather, huh?

Glaciers Reveal Martian Climate Has Been Recently Active. The prevailing thinking is that Mars is a planet whose active climate has been confined to the distant past. About 3.5 billion years ago, the Red Planet had extensive flowing water and then fell quiet - deadly quiet. It didn't seem the climate had changed much since. Now, in a research article that graces the May cover of Geology, scientists at Brown University think Mars' climate has been much more dynamic than previously believed. After examining stunning high-resolution images taken last year by the Mars Reconnaissance Orbiter, the researchers have documented for the first time that ice packs at least 1 kilometer (0.6 miles) thick and perhaps 2.5 kilometers (1.6 miles) thick existed along Mars' mid-latitude belt as recently as 100 million years ago. In addition, the team believes other images tell them that glaciers flowed in localized areas in the last 10 to 100 million years - akin to the day before yesterday in Mars' geological timeline.This evidence of recent activity means the Martian climate may change again and could bolster speculation about whether the Red Planet can, or did, support life.

Martian Secrets

A radar instrument co-sponsored by NASA on the European Space Agency's Mars Express orbiter has looked beneath the surface of Mars and opened up a new dimension for planetary exploration.
The technique's success is prompting scientists to think of other places in the solar system where they would like to use radar sounders. The radar sounder on Mars Express is the Mars Advanced Radar for Subsurface and Ionospheric Imaging, or MARSIS. It was built to map the distribution of liquid and frozen water in upper portions of the planet's crust.

Stephen Hawking calls for new era of space conquest

Theoretical physicist Stephen Hawking has called for a "new era" in space exploration similar to that of Christopher Columbus' discovery of the New World in 1492. Speaking at a special function honouring the 50th anniversary of NASA, Hawking compared the current situation in space exploration to that of Europe prior to Columbus' travels.

"People might well have argued it was a waste of money to send Columbus on a wild goose chase, Yet the discovery of the new world made profound difference to the old," he said, adding mischievously: "Just think, we would not have a Big Mac or KFC (Kentucky Fried Chicken)."

"Spreading out into space will have an even greater effect," he told an audience at George Washington University, Washington DC. "It will completely change the future of the human race and maybe determine whether we have any future at all."

Full article: http://www.thetechherald.com/article.php/200817/778/Stephen-Hawking-calls-for-new-era-of-space-conquest

-Ryan

Mission to the Moon

Several instruments that will help NASA characterize the Moon's surface have been installed on the Lunar Reconnaissance Orbiter, or LRO. The powerful equipment will bring the Moon into sharper focus and reveal new insights about the celestial body nearest Earth.
Engineers and technicians on the LRO Integration and Test Team work almost around the clock in a clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland, to ready the spacecraft for testing and eventual launch later this year.
Four of six instruments have been mated to the spacecraft, with one to be installed soon and one to arrive in the near future.
The satellite is scheduled to launch from NASA's Kennedy Space Center, Florida, in late 2008 on an Atlas V rocket. It will spend 1 year in low polar orbit on its primary exploration mission, with the possibility of 3 more years to collect additional detailed scientific information about the Moon and its environment. That information will help ensure a safe and productive human return to the Moon.

Full article: http://www.astronomy.com/asy/default.aspx?c=a&id=6850

Hawking: Yes to Alien Life. No to Intelligence

Astrophysicist Stephen Hawking recently talked about his views on the possibility of life in our universe in a speech at George Washington University to celebrate NASA's 50th anniversary. Hawking asserted that while intelligent life is very rare, baterial life is much more common and in fact likely throughout our universe.

http://news.yahoo.com/s/ap/20080421/ap_on_sc/stephen_hawking_3

New star

Today, I wrote a web-news story about a “new star” in the constellation Cygnus the Swan. In a bit of cross-promotion, I’d like to share the information as a blog.

Late at night on Thursday, April 10, Japanese amateur astronomers Koichi Nishiyama and Fujio Kabashima discovered a possible nova in the Swan. Astronomers initially catalog such events as variable stars. This one received the label V2491 Cygni. Follow-up observations by other astronomers confirmed the object was a nova. Recent estimates place its brightness at magnitude 7.6.

If you’re new to observational astronomy, the magnitude scale provides a way to compare the brightnesses of celestial objects. The brightest stars have magnitudes of 0 and 1, and the faintest stars visible to the unaided eye from a dark site typically have a magnitude around 6.5. The nova, therefore, lies just below the naked-eye visibility limit. This means you can spot V2491 Cygni easily through binoculars.

To spot the nova, use the finder chart at the bottom. Cygnus rises in the northeast and is fully visible just after 11 P.M. local time. It continues to climb higher in the sky until dawn. Tonight, the Moon is a few days after First Quarter. It sits across the sky in the constellation Leo the Lion. Moonset occurs around 3:30 A.M. local time. The nova shines brightly enough that moonlight will not interfere with the view.

If your sky is clear over the next week or so, you may want to sketch or photograph this region each night. Such images will show how the star brightens or fades, and are important in the study of novae. If you’re happy with the images you get, you can submit them to the American Association of Variable Star Observers at www.aavso.org.

A nova is an explosion resulting when hydrogen from one star of a binary system falls onto the surface of the second star, which is a white dwarf. White dwarfs represent the last stage in the lives of Sun-like stars. In such cases, the star shines like the Sun from a few billion to about 20 billion years. Energy production exhausts the nuclear fuel in its core, and the core shrinks. This heats up the core, causing the star’s outer layers to expand. As the core cools, it shrinks to form a white dwarf star.

Nishiyama, 70, is from Kurume, Fukuoka-Ken, and Kabashima, 68, from Miyaki-cho, Saga-ken. Both are well-known supernova hunters. Nishiyama takes images with the duo’s 16-inch (0.4 meter) reflector using a charge-coupled device (CCD) camera in their Miyaki Argenteus Observatory. Kabashima then analyzes the images with a personal computer.

picture of the day

Bacteriophages: The Most Common Life-Like Form on Earth
Credit: Wikipedia; Insert: Mike Jones

Explanation: There are more bacteriophages on Earth than any other life-like form. These small viruses are not clearly a form of life, since when not attached to bacteria they are completely dormant. Bacteriophages attack and eat bacteria and have likely been doing so for over 3 billion years ago. Although initially discovered early last century, the tremendous abundance of phages was realized more recently when it was found that a single drop of common seawater typically contains millions of them. Extrapolating, phages are likely to be at least a billion billion (sic) times more numerous than humans. Pictured above is an electron micrograph of over a dozen bacteriophages attached to a single bacterium. Phages are very small -- it would take about a million of them laid end-to-end to span even one millimeter. The ability to kill bacteria makes phages a potential ally against bacteria that cause human disease, although bacteriophages are not yet well enough understood to be in wide spread medical use.

The Race to Build the Biggest, Baddest Telescope Continues

Big telescope projects are vying for philanthropic dollars to gather light and knowledge from the farthest reaches of the universe and compete for the title of being the biggest and the baddest.

The Houston Chronicle ran an editorial Thursday about how Texas billionaire George Mitchell is heading up an effort to have Texas A&M and UT Austin help raise the $550 million to build a new 24.6 meter optical telescope in Chile. He has pledged $3.25 million towards the $55 million the universities need to raise to secure 10% of the observing time. The telescope will produce images 10 times sharper then Hubble.

A Californian/Canadian team is also looking at building the next "great telescope." Their plan is to build a Thirty Meter Telescope (TMT) and announced in December 2007 a $200 million dollar grant from the Gordon and Betty Moore Foundation towards the $300 million needed to build the instrument. This telescope is also optical (and infrared), also being built in Chile and will produce images 12 times sharper then Hubble. Each team says their facility will be operational by 2016 or 2017.

Full article here: http://blog.wired.com/wiredscience/2008/04/the-race-to-bui.html

-Ryan

Russio to stop space tourism

Russia plans to discontinue offering rides into space in 2010 says the chief of the Russian Space Agency. The decision to discontinue service is a result of plans to include six astronauts on space shuttles starting in 2010 instead of the three that currently go up with the shuttle, leaving far less room for space tourists.

full article - http://www.chinapost.com.tw/international/europe/2008/04/13/151669/Russia-plans.htm

Moon Mission

NASA's moon mission has just been improved as new instruments have been installed on the Lunar Reconnaissance orbiter (LRO). This will help make the moon pics. more focused and allow astronomers to learn even more. It has taken quite some time to get the LRO ready for its journey and according to the deputy project manager, Cathy Peddie, a lot of progress has been made. Check it out:

http://www.astronomy.com/asy/default.aspx?c=a&id=6850

Solar Flares Set The Sun Quaking

ScienceDaily (Apr. 18, 2008) — Data from the ESA/NASA spacecraft SOHO shows clearly that powerful starquakes ripple around the Sun in the wake of mighty solar flares that explode above its surface. The observations give solar physicists new insight into a long-running solar mystery and may even provide a way of studying other stars.

Want more?
http://www.sciencedaily.com/releases/2008/04/080418090439.htm

Asteroid Belt like Ours

About four years ago, an asteroid belt was found that was very similar to our own. Scientists believe that this belt may reveal planets in the making or the remnants of planets which used to orbit the star. The asteroid belt is located around a star about two times the size of the sun and much younger. This star, Zeta Leporis, is located 60-70 light years away.

The asteroid belt is made up of warm dust particles, particles that are closer to the star. These dust rings are often found on newly formed stars. However, particles like these should spiral into the star within about 20,000 years, but the star is much older than that. This means that the asteroid belt must be the result of some other occurrence like a collision of larger objects.

Astronomers found the temperature of the belt to be about 150 degrees Fahrenheit with a net mass of 1,000 times that of the Sun's asteroid belt. Additionally, the debris in the belt range from 2.5 to 12.2 Astronomical Units from the star. As you may remember, 1 AU is the distance from the Earth to the Sun.

It is possible that Zeta Leporis is orbited by planets. Though, our present technology cannot pinpoint one and researchers say that it may be years before we are able to produce enough evidence for the existence of smaller planets like Earth in Zeta Leporis's solar system.

Cited from:
http://www.space.com/scienceastronomy/astronomy/aas_solarsystems_010604.html

Stars born in galactic wilderness

Baby stars have been discovered spawning in the otherwise barren outskirts of a galaxy.

The finding has surprised astronomers because the galactic periphery was assumed to lack high concentrations of ingredients needed to form stars.

The stars can be seen in a new image of the Southern Pinwheel galaxy, or M83, obtained by a Nasa space telescope and a ground-based observatory.

They are forming more than 100,000 light-years from M83's bustling centre.

More here: http://news.bbc.co.uk/1/hi/sci/tech/7351516.stm

-Ryan

"Revolutionary" Cassini Mission is Extended

NASA's Cassini-Huygens spacecraft mission is extending its end date by 2 years. The discoveries and images have been so incredible that they have "revolutionized our knowledge of Saturn and its moons." The international mission was originally to end in Jully 2008 but is now being extended to include 60 more orbits of Saturn and more "flybys" of its moons. Check it out:

http://www.astronomy.com/asy/default.aspx?c=a&id=6820

Largest telescope would be out of this world

Dark Ages Lunar Interferometer could probe ‘dark ages’ of the universe
A telescope on the far side of the moon could probe the "dark ages" of the universe while blocking out the radio-wavelength noise of Earth civilizations.
Up to one hundred thousand antennas would form the Dark Ages Lunar Interferometer, the largest telescope ever built, and allow astronomers to hear faint whispering signals from a time when no stars even existed.
"This will look at one of the most fundamental questions ever conceived, back when the universe was made up almost entirely of hydrogen and helium — no stars, no galaxies," said Kurt Weiler, senior astronomer at the U.S. Naval Research Laboratory.
The so-called dark ages of astronomy describe a half-billion year period following the Big Bang when clouds of ionized gas cooled as the universe expanded. The only faint noise came from hydrogen atoms doing spin-flips, which gives off radio-wavelength signals that astronomers can pick up on. Scientists currently estimate that the universe is about 13.7 billion years old.
"What happens is that because of the Big Bang there's a background glow," Weiler noted. "The spin-flip will absorb the glow of the older material and will give us a signature that we can see."
However, the ongoing expansion of the universe has stretched or red-shifted the hydrogen signature from just around 8 inches to a number of feet. That means the signals can easily get masked by louder Earth transmissions in the same wavelength, unless astronomers find a quieter listening spot.
"The back side of the moon is the only place in the local universe shielded from manmade transmissions," Weiler told SPACE.com.
The DALI design resembles existing radio telescope arrays in the Netherlands, Australia and New Mexico. But sending such an array to the moon requires lighter material that can save on launch costs, not to mention survive the harsh lunar conditions.
getCSS("3053751")
Slide show

Space ShotsSee distant moons, a space capsule, the southern polar region of Mars and other out-of-this-world highlights in the latest installment of "Space Shots."
more photosOne candidate is polyimide, a plastic-like film which can act as an antenna when plated with metal. University of Colorado researchers are testing the film's durability by exposing it to harsh ultraviolet rays, as well as the extreme temperatures like that of boiling water and super-cold liquid nitrogen.
The film antennas would be rolled up and then unrolled for deployment across 30 miles of lunar surface, arrayed in one thousand stations containing one hundred antennas each. Still, getting the entire load to the moon represents a challenge.
"Even though each antenna may weigh a few ounces, you're talking about needing at least heavy lift vehicles," Weiler noted. "They all add up fast."
The U.S. Naval Research Laboratory is sharing NASA funding with an MIT-based team working on another lunar telescope separate from DALI. Their collaboration may finally realize a dream that many astronomers had even before the first Apollo landings on the moon.
"Probing the dark ages presents the opportunity to watch the young universe evolve," said Joseph Lazio, NRL astronomer and head of the DALI proposal. "Just as current cosmological studies have both fascinated and surprised us, I anticipate that DALI will lead both to increased understanding of the universe and unexpected discoveries."

Smallest Black Hole Ever Discovered Has Amazing Tidal Force

ScienceDaily (Apr. 2, 2008) — Using a new technique, two NASA scientists have identified the lightest known black hole. With a mass only about 3.8 times greater than our Sun and a diameter of only 15 miles, the black hole lies very close to the minimum size predicted for black holes that originate from dying stars.

Full story: http://www.sciencedaily.com/releases/2008/04/080401141549.htm

Milky Way's Giant Black Hole 'Awoke From Slumber' 300 Years Ago

ScienceDaily (Apr. 16, 2008) — Using NASA, Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that our galaxy’s central black hole let loose a powerful flare three centuries ago.

The finding helps resolve a long-standing mystery: why is the Milky Way’s black hole so quiescent? The black hole, known as Sagittarius A* (pronounced "A-star"), is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is billions of times weaker than the radiation emitted from central black holes in other galaxies.

More on this article? http://www.sciencedaily.com/releases/2008/04/080415111724.htm

Indian has new theory on Big Bang

A new controversial analysis by an astronomer of Indian origin has suggested that the Big Bang might not have come at the beginning of the Universe, but after a long and slow period of shrinkage.

According to a report, the theory has been put forward by Amit Yadav, an astronomer at the University of Illinois at Urbana-Champaign.

If this theory holds any ground, it would show that the early universe did not inflate with the smoothness that many theorists expected. "The standard, canonical models will be ruled out if this holds," said Yadav. "The simplicity is gone," he added.

If you are one of those who think this is great and are going to click the link because you want the entire article here you go!

http://www.dailyastronomy.com/story.asp?ID=279528&Title=Indian%20has%20new%20theory%20on%20Big%20Bang

NASA turns Green with Nationwide Earth Day Activities

WASHINGTON -- NASA centers across America will roll out the green carpet April 22 to celebrate Earth Day and reporters are invited to hear first hand about the agency's contributions to understanding and protecting our environment.

Need More?

visit: http://www.dailyastronomy.com/story.asp?ID=279607&Title=NASA%20Turns%20Green%20With%20Nationwide%20Earth%20Day%20Activities

Cassini receives extension

Cassini receives extension

Following success at Saturn, NASA extends the Cassini mission to July 2010.

Provided by NASA/JPL

In this computer artist's rendering, the Cassini spacecraft fires its engine in a maneuver that will place the spacecraft in orbit around Saturn. Dave Seal/JPL/NASA

April 16, 2008
NASA is extending the international Cassini-Huygens mission by 2 years. The historic spacecraft's stunning discoveries and images have revolutionized our knowledge of Saturn and its moons.

Cassini's mission originally had been scheduled to end in July 2008. The newly-announced 2-year extension will include 60 additional orbits of Saturn and more flybys of its exotic moons.

These will include 26 flybys of Titan, seven of Enceladus, and one each of Dione, Rhea and Helene. The extension also includes studies of Saturn's rings, its complex magnetosphere, and the planet.

"This extension is not only exciting for the science community, but for the world to continue to share in unlocking Saturn's secrets," says Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington, D.C.

"New discoveries are the hallmarks of its success, along with the breathtaking images beamed back to Earth that are simply mesmerizing," Green says.

"The spacecraft is performing exceptionally well and the team is highly motivated, so we're excited at the prospect of another 2 years," says Bob Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

Based on findings from Cassini, scientists think liquid water may be just beneath the surface of Saturn's moon, Enceladus. That's why the small moon, only one-tenth the size of Titan and one-seventh the size of Earth's Moon, is one of the highest-priority targets for the extended mission.

Cassini discovered geysers of water-ice jetting from the Enceladus' surface. The geysers, which shoot out at a distance three times the diameter of Enceladus, feed particles into Saturn's most expansive ring. In the extended mission, the spacecraft may come as close as 15 miles from the moon's surface.

Cassini's observations of Saturn's largest moon, Titan, have given scientists a glimpse of what Earth might have been like before life evolved. They now believe Titan possesses many parallels to Earth, including lakes, rivers, channels, dunes, rain, snow, clouds, mountains and possibly volcanoes.

"When we designed the original tour, we really did not know what we would find, especially at Enceladus and Titan," says Dennis Matson, the JPL Cassini project scientist. "This extended tour is responding to these new discoveries and giving us a chance to look for more."

Unlike Earth, Titan's lakes, rivers and rain are composed of methane and ethane, and temperatures reach a chilly minus 290° Fahrenheit (143° Celsius). Although Titan's dense atmosphere limits viewing the surface, Cassini's high-resolution radar coverage and imaging by the infrared spectrometer have given scientists a better look.

Other activities for Cassini scientists will include monitoring seasons on Titan and Saturn, observing unique ring events, such as the 2009 equinox when the Sun will be in the plane of the rings, and exploring new places within Saturn's magnetosphere.

Cassini has returned a daily stream of data from Saturn's system for almost 4 years. Its travel scrapbook includes nearly 140,000 images and information gathered during 62 revolutions around Saturn, 43 flybys of Titan and 12 close flybys of the icy moons.

More than 10 years after launch and almost 4 years after entering into orbit around Saturn, Cassini is a healthy and robust spacecraft. Three of its science instruments have minor ailments, but the impact on science-gathering is minimal. The spacecraft will have enough propellant left after the extended mission to potentially allow a third phase of operations. Data from the extended mission could lay the groundwork for possible new missions to Titan and Enceladus.

Cassini launched October 15, 1997, from Cape Canaveral, Florida, on a 7-year journey to Saturn, traversing 2.2 billion miles (3.5 billion kilometers). It is one of the most scientifically capable spacecraft ever launched, with a record 12 instruments on the orbiter and six more instruments on the European Space Agency's Huygens probe, which piggybacked a ride to Titan on Cassini.

Cassini receives electrical power from three radioisotope thermoelectric generators, which generate electricity from heat produced by the natural decay of plutonium. The spacecraft was captured into Saturn orbit in June 2004 and immediately began returning data to Earth.

Milky way's Black hole

Milky Way's black hole wakes up

Our galaxy's giant black hole erupted 300 years ago.

Provided by NASA's Goddard Space Flight Center

This Chandra image shows our galaxy’s center. The location of the black hole, known as Sagittarius A*, or Sgr A* for short, is arrowed. NASA/CXC/MIT/Frederick K. Baganoff et al. [View Larger Image] April 15, 2008 Using NASA, Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that our galaxy's central black hole let loose a powerful flare 3 centuries ago. The finding helps resolve a long-standing mystery: why is the Milky Way's black hole so quiescent? The black hole, known as Sagittarius A* (pronounced "A-star"), is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is billions of times weaker than the radiation emitted from central black holes in other galaxies. "We have wondered why the Milky Way's black hole appears to be a slumbering giant," says team leader Tatsuya Inui of Kyoto University in Japan. "But now we realize that the black hole was far more active in the past. Perhaps it's just resting after a major outburst." The new study, which will appear in the Publications of the Astronomical Society of Japan, combines results from Japan's Suzaku and ASCA X-ray satellites, NASA's Chandra X-ray Observatory, and the European Space Agency's XMM-Newton X-ray Observatory. The observations, collected between 1994 and 2005, revealed that clouds of gas near the central black hole brightened and faded quickly in X-ray light as they responded to X-ray pulses emanating from just outside the black hole. When gas spirals inward toward the black hole, it heats up to millions of degrees and emits X-rays. As more and more matter piles up near the black hole, the greater the X-ray output.

An X-ray satellite imaged a small region in the gas cloud Sagittarius B2, and saw pockets brighten and fade over the course of nearly 12 years. These light echoes are caused by varying X-ray output from our galaxy’s central black hole. JAXA [View Larger Image]

These X-ray pulses take 300 years to traverse the distance between the central black hole and a large cloud known as Sagittarius B2, so the cloud responds to events that occurred 300 years earlier. When the X-rays reach the cloud, they collide with iron atoms, kicking out electrons that are close to the atomic nucleus. When electrons from farther out fill in these gaps, the iron atoms emit X-rays. But after the X-ray pulse passes through, the cloud fades to its normal brightness.

Amazingly, a region in Sagittarius B2 only 10 light-years across varied considerably in brightness in just 5 years. These brightenings are known as light echoes. By resolving the X-ray spectral line from iron, Suzaku's observations were crucial for eliminating the possibility that subatomic particles caused the light echoes.

"By observing how this cloud lit up and faded over 10 years, we could trace back the black hole's activity 300 years ago," says team member Katsuji Koyama of Kyoto University. "The black hole was a million times brighter 3 centuries ago. It must have unleashed an incredibly powerful flare."

This new study builds upon research by several groups who pioneered the light-echo technique. Last year, a team led by Michael Muno, who now works at the California Institute of Technology, used Chandra observations of X-ray light echoes to show that Sagittarius A* generated a powerful burst of X-rays about 50 years ago — about a dozen years before astronomers had satellites that could detect X-rays from outer space. "The outburst three centuries ago was 10 times brighter than the one we detected," says Muno.

The galactic center is about 26,000 light-years from Earth, meaning we see events as they occurred 26,000 years ago. Astronomers still lack a detailed understanding of why Sagittarius A* varies so much in its activity. One possibility, says Koyama, is that a supernova a few centuries ago plowed up gas and swept it into the black hole, leading to a temporary feeding frenzy that awoke the black hole from its slumber and produced the giant flare.

picture of the day

A Protected Night Sky Over Flagstaff
Credit and Copyright: Dan & Cindy Duriscoe, FDSC, Lowell Obs., USNO

Explanation: This sky is protected. Yesterday marked the 50 year anniversary of the first lighting ordinance ever enacted, which restricted searchlight advertisements from sweeping the night skies above Flagstaff, Arizona, USA. Flagstaff now enjoys the status of being the first International Dark Sky City, and maintains a lighting code that limits lights from polluting this majestic nighttime view. The current dark skies over Flagstaff not only enable local astronomers to decode the universe but allow local sky enthusiasts to see and enjoy a tapestry contemplated previously by every human generation. The above image, pointing just east of north, was taken two weeks ago at 3 am from Fort Valley, only 10 kilometers from central Flagstaff. Visible in the above spectacular panorama are the San Francisco Peaks caped by a lenticular cloud. Far in the distance, the plane of the Milky Way Galaxy arcs diagonally from the lower left to the upper right, highlighted by the constellations of Cassiopeia, Cepheus, and Cygnus. On the far right, the North America Nebula is visible just under the very bright star Deneb.

German schoolboy, 13, corrects NASA's asteroid figures: paper

BERLIN (AFP) - A 13-year-old German schoolboy corrected NASA's estimates on the chances of an asteroid colliding with Earth, a German newspaper reported Tuesday, after spotting the boffins had miscalculated.

Nico Marquardt used telescopic findings from the Institute of Astrophysics in Potsdam (AIP) to calculate that there was a 1 in 450 chance that the Apophis asteroid will collide with Earth, the Potsdamer Neuerster Nachrichten reported.

NASA had previously estimated the chances at only 1 in 45,000 but told its sister organisation, the European Space Agency (ESA), that the young whizzkid had got it right.

Full story: http://news.yahoo.com/s/afp/20080415/sc_afp/spaceastronomygermany_080415214429

-Ryan

Space Junk swirling around Earth Orbit.

Not only our atmosphere and oceans are being polluted by billions of pieces of junk.

As these computer-generated images show, Mankind's seemingly insatiable desire to litter has now extended out into space, with potentially devastating results.

Rocket scientists call it 'orbital debris'; everyone else calls it space junk. And it is becoming a probleme put our first object into space just 51 years ago - Sputnik One.

But in just half a century we have created a swarm of perhaps tens of millions of items of debris, all circling around the planet - rubbish through which the 600-odd operating satellites, one space station, one space telescope, an occasional space shuttle, interplanetary probe and Soyuz rockets have to negotiate a safe passage.

As the images show, these form distinct rings and spheres around Earth.

Most hug close to the surface, 200-300 miles up in low-earth-orbit, where they pose a potentially deadly hazard to astronauts and their spacecraft before they burn up in the atmosphere, usually a few months later.

New Planet found in Constellation Leo

Spanish and UCL (University College London) scientists have discovered a possible terrestrial-type planet orbiting a star in the constellation Leo. The new planet, which lies at a distance of 30 light-years from Earth, has a mass five times that of our planet but is the smallest found to date. One full day on the new planet would be equivalent to three weeks on Earth. I thought this was interesting and figured I'd share it with you. If you want to see the full article click on the link below.

-Dusty
http://www.astronomy.com/asy/default.aspx?c=a&id=6803

May 25th NASA landing on Mars

http://www.astronomy.com/asy/default.aspx?c=a&id=6813

This article I found is about the fine tuning of the trajectory of the Pheonix spacecraft which is on a mission to mars and is supposed to land their on May 25th in the northern polar region of the red planet. The article is quite interesting, click on the link to check it out.

-Dusty

New Technique Can Estimate Size and Frequency of Meteorite Impacts

News today from the National Science Foundation will have an impact on how scientists are able to study…. well, impacts. A team of geologists has developed a new way of determining the size and frequency of meteorites that have collided with Earth in the past. By studying sediments found on the ocean floor and looking for isotopes of the rare element osmium, scientists can now figure out not only when a meteorite impact occurred in Earth’s history, but also the size of the meteorite. Written by Nancy Atkinson

http://www.universetoday.com/2008/04/14/new-technique-can-estimate-size-and-frequency-of-meteorite-impacts/#more-13649

A Super Cold Brown Dwarf

The coldest known stellar object was found by an international astronomy team when they discovered a brown dwarf with a temperature of approx. 350 degrees C. It was found using telescopes from around the world, including Hawaii and Chile. The star was named CFBDS J005910.83-011401.3 and and it is about 40 light-years away from our solar system. Check it out:

http://www.astronomy.com/asy/default.aspx?c=a&id=6808

Quasars Quash Star Formation In Active Galactic Nuclei

ScienceDaily (Apr. 9, 2008) — An ambitious study of active and inactive galaxies has given new insights into the complex interaction between super-massive black holes at the heart of Active Galactic Nuclei (AGN) and star formation in the surrounding galaxy. Results will be presented in a talk by Paul Westoby on 4th April at the RAS National Astronomy Meeting in Belfast.

For Full Article: http://www.sciencedaily.com/releases/2008/04/080404200325.htm

NASA Sets Sights On Lunar Dust Exploration Mission

ScienceDaily (Apr. 13, 2008) — NASA is preparing to send a small spacecraft to the moon in 2011 to assess the lunar atmosphere and the nature of dust lofted above the surface.

For Full Article: http://www.sciencedaily.com/releases/2008/04/080411092032.htm

Sun To Destroy Earth: Mankind to face extinction

According to a new scientific paper, scientists say that the sun, is going to destroy the earth. It would become so hot that the earth would become uninhabitable, and mankind will die out. But, I for one am not worried. How much time do we have? 7.6 Billion years. I think I should get started on my Bucket List.

There currently isn’t a sun cream in existence with sufficient factor value to counteract the upcoming bombardment our solar system’s star will eventually unleash upon the Earth, according to predictions issued by astronomers at the University of Sussex.

We can only hope that 7.6 billion years of evolution, which is how long those astronomers are suggesting it will take for the expanding Sun to absorb the Earth, is sufficient time to see mankind long since gone amid the stars.

More here: http://www.thetechherald.com/article.php/200809/219/The-Sun-will-destroy-planet-Earth-in-7-6bn-years

Running Man

Thought this was a cool picture of something that we can see with a pretty simple telescope.

Visible to the naked eye as the middle "star" in Orion's "sword," this spectacular object looks great through any size telescope and at any magnification.

Move north of the Orion Nebula to find the Running Man Nebula (NGC 1973-5-7). The two bright stars involved with the nebula are 42 Orionis (magnitude 4.6) and 45 Orionis (magnitude 5.2). Because the Running Man Nebula is a reflection nebula, observe it without a nebula filter. Its light is reflected starlight scattered throughout the gas and dust, not reddish light emitted by hydrogen (which a nebula filter transmits).

www.astronomy.com

Rare Supernova Found.

Astronomers have spied a faraway star system that is so unusual, it was one of a kind -- until its discovery helped them pinpoint a second one that was much closer to home.

In a paper published in a recent issue of the Astrophysical Journal Letters, Ohio State University astronomers and their colleagues suggest that these star systems are the progenitors of a rare type of supernova.

They discovered the first star system 13 million light years away, tucked inside Holmberg IX, a small galaxy that is orbiting the larger galaxy M81. They studied it between January and October 2007 with the Large Binocular Telescope (LBT) on Mt. Graham in Arizona.

The star system is unusual, because it’s what the astronomers have called a “yellow supergiant eclipsing binary” -- it contains two very bright, massive yellow stars that are very closely orbiting each other. In fact, the stars are so close together that a large amount of stellar material is shared between them, so that the shape of the system resembles a peanut.

In a repeating cycle, one star moves to the front and blocks our view of the other. From Earth, the star system brightens and dims, as we see light from two stars, then only one star.

The two stars in this system appear to be nearly identical, each 15 to 20 times the mass of our sun.

José Prieto, Ohio State University graduate student and lead author on the journal paper, analyzed the new star system as part of his doctoral dissertation. In his research, he scoured the historical record to determine whether his group had indeed found the first such binary.

To his surprise, he uncovered another one a little less than 230,000 light years away in the Small Magellanic Cloud, a small galaxy that orbits our own Milky Way.

The star system had been discovered in the 1980s, but was misidentified. When Prieto re-examined the data that astronomers had recorded at the time, he saw that the pattern of light was very similar to the one they had detected outside of M81. The stars were even the same size -- 15 to 20 times the mass of the sun -- and melded together in the same kind of peanut shape. The system was clearly a yellow supergiant eclipsing binary.

“We didn’t expect to find one of these things, much less two,” said Kris Stanek, associate professor of astronomy at Ohio State. “You never expect this sort of thing. But I think this shows how flexible you have to be in astrophysics. We needed the 8.4-meter LBT to spot the first binary, but the second one is so bright that you could see it with binoculars in your back yard. Yet, if we hadn’t found the first one, we may never have found the second one.”

“It shows that there are still valuable discoveries hidden in plain sight. You just have to keep your eyes open and connect the dots.”

The find may help solve another mystery. Of all the supernovae that have been studied over the years, two have been linked to yellow supergiants -- and that’s two more than astronomers would expect.

Prieto explained why. Over millions of years, a star will burn hotter or cooler as it consumes different chemical elements in its core. The most massive stars swing back and forth between being cool red supergiants or hot blue ones. They spend most of their lives at one end of the temperature scale or the other, but spend only a short time in-between, where they are classified as yellow. Most stars end their life in a supernova at the red end of the cycle; a few do at the blue end. But none do it during the short yellow transitional phase in between.

At least, that’s what astronomers thought.

Prieto, Stanek, and their colleagues suspect that yellow binary systems like the ones they found could be the progenitors of these odd supernovae.

“When two stars orbit each other very closely, they share material, and the evolution of one affects the other,” Prieto said. “It’s possible two supergiants in such a system would evolve more slowly, and spend more time in the yellow phase -- long enough that one of them could explode as a yellow supergiant.”

The discovery of this yellow supergiant binary system is just the first result of a long-term LBT project to monitor stellar variability in the nearby universe. That project is led by Ohio State professor of astronomy, Chris Kochanek. He and Rick Pogge, also a professor of astronomy, are coauthors on the paper in Astrophysical Journal Letters.

Their collaborators were from the University of Minnesota, the Osservatorio Astronomico di Padova, Steward Observatory, the Max-Planck-Institut für extraterrestrische Physik, the Osservatorio Astronomico di Roma, the University of Notre Dame, and the Large Binocular Telescope Observatory. They used observations from the 8.4-meter LBT and from the 2.4-meter telescope at the nearby MDM observatory.

The LBT is an international collaboration among institutions in the United States, Italy and Germany. The LBT Corporation partners are: the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; Ohio State University; The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

This research was funded by the National Science Foundation.