Clipmarks | tabsey's 'astronomy' clips

No naked black holes

Tue, 07 Oct 2008 13:33:41 GMT

clipped by: tabsey
clipper's remarks: Winter woollies and a scuba outfit and off you go.

The Cassini spacecraft observations of Saturn's largest moon, the orange-colored 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.

"Titan is just covered in carbon-bearing material -- it's a giant factory of organic chemicals," according to Ralph Lorenz of Johns Hopkins University Applied Physics Laboratory. "We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe."

"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,

minus 290 degrees Fahrenheit

Tags: astronomy

No naked black holes

Tue, 07 Oct 2008 12:56:48 GMT

clipped by: tabsey
clipper's remarks: The video is simplistic but effective.

Clip Source: www.sciencenews.org

No matter how hard you try to push their boundaries, black holes always seem to preserve their modesty. Indiscreet astrophysicists have simulated the most violent collisions of black holes yet, and found that the resulting black hole still has an event horizon — the surface through which even light cannot escape and that hide black holes’ interiors.

An international team of researchers created a computer simulation of what they call the most violent collision imaginable: Two black holes of equal masses smashing into each other head-on, moving at close to the speed of light.

Previous studies have suggested that when black holes collide they merge into one larger black hole, radiating huge amounts of energy in the form of gravitational waves — ripples in the very shape of space — that travel at the speed of light. This study’s results were no exception.

HEAD-ONVIDEO | A computer simulation shows that two black holes of equal mass colliding at close to the speed of light

Tags: astronomy

Two Spiral Galaxies Collide

Thu, 02 Oct 2008 09:23:02 GMT

clipped by: tabsey
clipper's remarks: There goes the weekender.

Clip Source: news.yahoo.com

Hubble & Spitzer Space Telescopes

Tags: astronomy

Where In The Universe Challenge #22

Mon, 29 Sep 2008 15:22:43 GMT

clipped by: tabsey
clipper's remarks: I got the planet right but had never seen a pic of this place.

Clip Source: www.universetoday.com

It's time once again for this week's Where In The Universe challenge. Take a look at the image above and try to determine where in the universe this image was taken. Give yourself extra points if you can name the spacecraft responsible for taking this image. As always, no peeking below before you make your guess. And comments are welcome if you want to share how well you did!

Make your guess, and then proceed.
Click to continue…

Filed under: Where In the Universe? | 18 Comments »

Tags: astronomy

Is a Dark-Matter Galaxy Orbiting the Milky Way?

Thu, 25 Sep 2008 12:33:01 GMT

clipped by: tabsey

Clip Source: www.dailygalaxy.com

We now know about two dozen of these satellite galaxies. One of the most recent is "Segue 1", uncovered by the Sloan Digital Sky Survey (SDSS), whose extremely low light-to-mass ratio makes it a particularly significant cosmic find. Despite having a mass of a million suns it is nowhere near as luminous as astronomers would expect, with only a couple of hundred stars visible. They think "How can so much matter be so dark?", then they go "Dark matter!" and at this point we like to believe their monocle flies out and they dash down the street shouting Eureka.

Of course, the actual physics of arriving at this conclusion is a tiny bit more complicated, but the result is the same: Marla Geha (Yale professor of astronomy) and colleagues believe that it's a galaxy composed mainly of dark matter. A handy thing to have around when you're trying to study the stuff or even prove that it exists.

These mini-galaxies and other previously unobservable objects offer a wealth of data on galaxy formation

Tags: astronomy

The President's Management Agenda

Wed, 24 Sep 2008 12:00:37 GMT

clipped by: tabsey
clipper's remarks: Found this at the bottom of a NASA page.

Clip Source: www.nasa.gov

From the President's Management Agenda:

To reform government, we must rethink government.

The need for reform is urgent. The General Accounting Office (GAO) "high-risk" list identifies areas throughout the federal government that are most vulnerable to fraud, waste, and abuse. Ten years ago, the GAO found eight such areas. Today it lists 22. Perhaps as significant, government programs too often deliver inadequate services at excessive cost. . . .

So while government needs to reform its operations--how it goes about its business and how it treats the people it serves, it also needs to rethink its purpose--how it defines what business is and what services it should provide.

The President's vision for government reform is guided by three principles. Government should be:

Citizen-centered, not bureaucracy-centered;

Results-oriented;

Market-based, actively promoting rather than stifling innovation through competition.

Read the full report.

Tags: astronomy

Solar Wind Loses Power, Hits 50-year Low

Wed, 24 Sep 2008 11:47:55 GMT

clipped by: tabsey
clipper's remarks: Can recommend the whole article.

Clip Source: science.nasa.gov

Sept. 23, 2008: In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.

"The average pressure of the solar wind has dropped more than 20% since the mid-1990s," says Dave McComas of the Southwest Research Institute in San Antonio, Texas. "This is the weakest it's been since we began monitoring solar wind almost 50 years ago."

McComas is principal investigator for the SWOOPS solar wind sensor onboard the Ulysses spacecraft, which measured the decrease. Ulysses, launched in 1990, circles the sun in a unique orbit that carries it over both the sun's poles and equator, giving Ulysses a global view of solar wind activity:

Above: Global measurements of solar wind pressure by Ulysses. Green curves trace the solar wind in 1992-1998, while blue curves denote lower pressure winds in 2004-2008. [Larger image]

The heliosphere. Click to view a larger image showing the rest of the bubble.

The solar wind isn't inflating the heliosphere as much

Tags: astronomy

Scientists Detect "Dark Flow:" Matter From Beyond the Visible Universe

Wed, 24 Sep 2008 11:25:19 GMT

clipped by: tabsey
clipper's remarks: The article makes more sense than my clipping.

Clip Source: www.universetoday.com

Scientists Detect "Dark Flow:" Matter From Beyond the Visible Universe

Just as unseen dark energy is increasing the rate of expansion of the universe, there's something else out there causing an unexpected motion in distant galaxy clusters. Scientists believe the cause is the gravitational attraction of matter that lies beyond the observable universe, and they are calling it "Dark Flow," in the vein of two other cosmological mysteries, dark matter and dark energy. "The clusters show a small but measurable velocity that is independent of the universe's expansion and does not change as distances increase," said lead researcher Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md. "The distribution of matter in the observed universe cannot account for this motion."

"We never expected to find anything like this," he said.

"Because the dark flow already extends so far, it likely extends across the visible universe," Kashlinsky says.

Tags: astronomy

Sun May Be Galactic Hitchhiker

Mon, 22 Sep 2008 13:24:54 GMT

clipped by: tabsey
clipper's remarks: I knew Adams was right. We will be in the way of a cyber by-pass.

Clip Source: news.yahoo.com

Astronomers have long believed that most stars are homebodies which stick close to their birthplaces. But a new simulation supports the suggestion that our sun might have once hitchhiked through the galaxy.

Where our sun or another star ends up migrating seems to depend on its position in a spinning spiral galaxy. Stars tagging along behind a massive spiral arm can get a gravitational speed boost that sends them into a bigger orbit around the galactic center. The stars leading in front of a spiral arm may end up getting slowed by the arm's gravitational pull and fall back into a smaller orbit.

"Our simulation is still like a toy model, but a step more complex than the ones observing migrations before," said Rok Roskar, an astronomer at the University of Washington in Seattle.

Previous simulations followed star migration in a preset galaxy. The new computer model goes back 9 billion years to track a galaxy's evolution from a giant cloud of gas.

Tags: astronomy, earth

Stardust evidence points to planet collision

Sat, 20 Sep 2008 13:11:15 GMT

clipped by: tabsey
clipper's remarks: A new possibility for the Armageddonites.

Clip Source: news.yahoo.com

WASHINGTON (Reuters) - Masses of dust floating around a distant binary star system suggest that two Earth-like planets obliterated each other in a violent collision, U.S. researchers reported on Friday.

"It's as if Earth and Venus collided with each other," Benjamin Zuckerman, an astronomer at the University of California Los Angeles, who worked on the study, said in a statement.

"Astronomers have never seen anything like this before; apparently major, catastrophic, collisions can take place in a fully mature planetary system."

Writing in the Astrophysical Journal, the team at UCLA, Tennessee State University and the California Institute of Technology said it spotted the dust orbiting a star known as BD +20 307, 300 million light-years from Earth in the constellation Aries.

"If any life was present on either planet, the massive collision would have wiped out everything in a matter of minutes: the ultimate extinction event," said Gregory Henry of Tennessee State University.

Tags: astronomy

First Ever Image of Alien Planet Captured

Thu, 18 Sep 2008 16:18:59 GMT

clipped by: tabsey
clipper's remarks: The article says it could be lots of things.

Clip Source: www.dailygalaxy.com

Astronomers believe they have captured the first picture of an alien planet in orbit around a star that is similar to our own Sun, called 1RXS J160929.1-210524, which is similar in mass to the Sun, but is much younger.. Located around 500 light-years from Earth, the planet in the snapshot is around eight times bigger than Jupiter, the biggest in our solar system and lies more than ten times further from its star than the sun does from Neptune.

The work that led to this discovery is part of a survey of more than 85 stars in the Upper Scorpius association, a group of young stars formed about 5 million years ago. It uses the Gemini telescope's high-resolution adaptive optics capabilities to determine the different types of companions that can form around young stars: stars, brown dwarfs, or planetary mass objects. “This discovery certainly has us looking forward to what other surprises nature has in stock for us,” said Marten van Kerkwijk,
Professor of Astronomy at the University of Toron

Tags: astronomy

Dark matter 'bridge to nowhere' found in cosmic void

Mon, 15 Sep 2008 16:40:51 GMT

clipped by: tabsey

Clip Source: space.newscientist.com

A line of 14 galaxies seems to be strung along a filament of dark matter.

More than a dozen galaxies seem to be lined up along a bridge of dark matter inside a region of nearly empty space. This 'bridge to nowhere' could shed light on how small galaxies formed in the early universe.

Galaxies in the universe are arranged in a lacy structure that contains many holes, or voids, that are largely bereft of galaxies. But the voids are not completely empty; astronomers expect they are criss-crossed by filaments of dark matter.

Now, astronomers have found a total of 14 galaxies that appear to be part of a dark matter bridge at least 1.5 million light years long.

The string of galaxies spans just 0.5% of a 'mini-void' – a region of space containing mostly dim, dwarf galaxies kept small by their relative isolation from other matter. But the underlying dark matter bridge may be far longer than that.

noticed that they all seemed to be arrayed in a line.

Tags: astronomy

Naked-Eye Gamma-ray Burst Aimed Directly at Earth

Fri, 12 Sep 2008 15:01:08 GMT

clipped by: tabsey
clipper's remarks: If you click on the word "click" it will bring up your player and show you an animated version of the picture. Have to be keen.

Clip Source: science.nasa.gov

Sept. 10, 2008: Astronomers announced today that a remarkable gamma-ray burst visible to the human eye earlier this year came from an explosive stellar jet aimed almost directly at Earth.

Right: Click to view a streaming animation of the explosive stellar jet, an artist's concept.

NASA's Swift satellite detected the explosion - formally named GRB 080319B - at 2:13 a.m. EDT on March 19, 2008, and pinpointed its position in the constellation Bootes. The gamma-ray burst became bright enough to see even without a telescope. Observations of the event by a global array of satellites and ground-based observatories have since given scientists the most detailed portrait of a burst ever recorded.

"Swift was designed to find unusual bursts," said Swift principal investigator Neil Gehrels at NASA's Goddard Space Flight Center in Greenbelt, Md. "We really hit the jackpot with this one."

Tags: astronomy

Galactic Diamonds -The Asteroid Steins The first images from Rosetta’s OSIRIS imaging system and V

Thu, 11 Sep 2008 17:04:28 GMT

clipped by: tabsey
clipper's remarks: All seen so far away.

Clip Source: www.dailygalaxy.com

The first images from Rosetta’s OSIRIS imaging system and VIRTIS infrared spectrometer were derived from raw data and have delivered breathtaking results.

"Steins looks like a diamond in the sky," said Uwe Keller, Principal Investigator for the OSIRIS imaging system from the Max Planck Institute.

[Video]

Visible in the image are several small craters on the asteroid, and two huge ones, one of which is 2 km in diameter, indicating that the asteroid must be very old.

Rita Schulz, Rosetta Project Scientist, said, "In the images is a chain of impact craters, which must have formed from recurring impact as the asteroid rotated. The impact may have been caused by a meteoroid stream, or fragments from a shattered small body."

The chain is composed of about 7 craters. To determine the age of the asteroid, a count of the craters on the asteroid’s surface has been started (the more the number of craters, the older the asteroid). So far, 23 craters have been spotted.

Tags: astronomy

Scream of Black Hole's Birth Detected Halfway Across the Universe

Thu, 11 Sep 2008 16:21:36 GMT

clipped by: tabsey
clipper's remarks: A good read for astronomical brains.

Clip Source: www.livescience.com

Six months ago, satellite telescopes spotted an exceptionally bright burst of energy that would have been the most distant object in the universe ever visible to the naked eye, if anyone saw it.

Even though no humans have reported seeing it directly, the gamma-ray burst, an explosion that signals the violent death of a massive star, is changing theories of how these events look. Gamma ray bursts are typically accompanied by intense releases of other forms of radiation, from X-rays to visible light.

This burst, dubbed GRB 080819B, was first detected by the Swift satellite on March 19, while the spacecraft was serendipitously looking at another gamma-ray burst in the same area of the sky.

The incredible amount of energy given off across the entire electromagnetic spectrum during a gamma-ray burst is what Jonathan Grindlay of the Harvard-Smithsonian Center for Astrophysics calls "the birth pangs of a black hole. This is the scream."

Tags: astronomy