Astrosphere for May 22, 2007

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Once again, let’s see what’s happening around the astrosphere.

First, I’d like to remind you that I’ll be hosting the 4th Carnival of Space here at Universe Today. Write a space-related story, submit it to me, and I’ll link to it from the Carnival. You’ll get lots of new readers coming to your blog. Here’s a link to the instructions on how to participate.

There’s a bit of a frenzy going on with a certain presidential candidate’s blog. Apparently, somebody doesn’t think the Sun is the centre of the Solar System. Both astropixie and Cocktail Party Physics have the scoop on this.

Vern’s Weblog has another list of things you can see in the night sky this week, as well as a few pictures captured through his telescope.

Astroblog has a nice picture of the Moon and Venus together in the sky.

Remember when I mentioned that May 19 was International Sidewalk Astronomy night? Top of the Lawn blog has a report of how the night went in New York City.

Did an exploding comet wipe out the large mammals of North America 13,000 years ago? Skymania News has a story on this interesting research.

International Sidewalk Astronomy Night – May 19, 2007

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I’m sorry this is such late notice, nobody let me know this was happening. Although sidewalk astronomers have been hitting the streets in the US for years, Saturday, May 19, 2007 is going to be the first International Sidewalk Astronomy Night.

If you’ve never heard of Sidewalk Astronomy, it’s an absolutely ingenious idea founded by John Dobson – inventor of the Dobsonian telescope. Amateur astronomers take their trusty telescopes out to public locations, like parks and busy streets, and give the general public a chance to see some of the most spectacular objects. They time the events so that major planets, the Moon, etc are visible in the early evening; objects visible from light polluted skies.

And this year, that evening is May 19.

Unlike previous years, the event is going international. Amateur astronomers will be setting up their scopes across the entire planet, from San Francisco to Sao Paulo to Kharkov. The event organizers are hoping to get 1,000 telescopes set up across the planet, engaging the public in astronomy.

If you’re an amateur astronomer, and want to help out, or if you want to find out where an event is happening near you so you can check out what they have to offer, visit their site here.

Sensitive Gemini Instrument Damaged

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A key scientific instrument attached to the Gemini South observatory was damaged in late April when a malfunctioning heater raised its temperature to 200-degrees Celsius. It was never meant to withstand temperatures this high, and will be out of commission for several months while technicians make repairs.

The device is called Gemini Near Infrared Spectrometer (GNIRS), and it measures the spectrum of light coming from a distant object, to help astronomers understand its composition.

On the weekend of April 20th, technicians were using a system that warms up the instrument between observations, and it was left running for several days. This is standard procedure; however, an independent controller that shuts off power to the heater failed, and allowed the heater to reach 200-degrees.

Once they realized the instrument was being cooked by the heater, the technicians shut it down and allowed it to cool for a few days. They removed the instrument from the telescope, and dismantled it to access the damage.

Unfortunately, portions of GNIRS were damaged, and the CCD science detector was completely destroyed. Most of the instrument is undamaged, but it will still take several months to examine each component, clean and replace the damaged ones, and retest it for astronomical duty.

Original Source: Gemini News Release

Spitzer Shows Young Stars Hatching in Orion

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The latest image released from the Spitzer Space Telescope shows infant stars “hatching” in the head of Orion. Astronomers think that a supernova 3 million years ago sent shockwaves through the region, collapsing clouds of gas and dust, and beginning a new generation of star formation.

The region imaged by Spitzer is called Barnard 30, located about 1,300 light-years from Earth in the constellation of Orion. More specifically, it’s located right beside the star considered to be Orion’s head, Lambda Orionis.

Since the region is shrouded in dark clouds of gas and dust that obscure visible light images, this was an ideal target for Spitzer, which can peer right through them in the infrared spectrum. The tints of orange-red glow are dust particles warmed by the newly forming stars. The reddish-pink dots are the young stars themselves, embedded in the clouds of gas and dust.

Original Source: Spitzer News Release

Astrosphere for May 18, 2007

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I didn’t do the astrosphere yesterday because of the Carnival of Space yesterday. But here we are again, with a whole new collection of stories.

But first, I’m going to be hosting the 4th Carnival of Space one more time next week, before passing the torch along. If you want to get involved this week, email me a link to a blog post that you’ve written, and I’ll link to it.

NASA has released new images showcasing their Constellation Program. Now you can get a better idea of what the spacecraft and landing systems are going to look like. Thanks to the Rocketry Blog for the tip.

I’m eyeing a Celestron SkyScout as a potential gadget to buy. The Astroprof, has a review.

Astroblog has a nice graphic put together for what you’ll see if you head outside on Sunday, May 20 and look to the West: Venus and the Moon close together.

Alan Boyle at the Cosmic Log is reporting that James “Scotty” Doohan’s ashes have been recovered, after the memorial spacecraft carrying them went missing for 2 weeks.

Bad Astronomy’s Phil Plait has stepped up and made a public apology after acting insensitive on his blog to a woman who suffered an internal decapitation, and survived.

PBS ran a demonstration of 3 different science shows last Fall, letting people vote for the one they like best. The clear winner to me was Wired Science, based on the magazine. Well, PBS thought so too, and is going to go ahead with it. Woohoo! Thanks to the Scientific American blog for the tip.

Supermassive Black Holes Set to Merge

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Astronomers have located an ongoing galactic merger, pinpointing the exact location of each galaxy’s supermassive black hole. These twin monsters are swirling around each other, and in several million years, they’ll merge together, releasing a powerful blast of gravitational radiation.

The twin galaxies are collectively known as NGC 6240, located about 300 million light years away, and they were recently imaged by the powerful adaptive optics system of the W.M. Keck Observatory in Hawaii. Under Keck’s vision, NGC 6240 was revealed to have two rotating disks of stars, each of which had its own supermassive black hole.

Millions of years ago, these would have been two separate galaxies that got to close to one another, and began merging. This process of galactic evolution is similar to the process that built up our own Milky Way, over billions of years. Astronomers are starting to understand the connection between the black holes and the total mass of the galaxy that surrounds them. As galaxies grow, the mass of their supermassive black holes grows too.

The twin supermassive black holes are slowly falling in to a common centre of gravity. In the next 10 to 100 million years, they’ll spiral into each other and merge into a single black hole. This collision will release waves of gravitational radiation.

Original Source: UCSC News Release

Saturn’s Rings in Blue

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I thought I’d highlight this recent Cassini image of Saturn, it’s just so cool looking. What you’re seeing is a view of Saturn from high above the planet’s northern latitudes, providing nearly a full view of the main rings, from the C ring to the A ring.

Why are the rings blue? Cassini captured this image in three different wavelengths of infrared light, and then they were matched on computer to the colours red, green and blue. So, this isn’t what you’d see with your eyes, but it helps reveal subtle differences on the planet and its rings.

The image was captured on April 5, 2007 when Cassini was approximately 1.4 million kilometers (900,000 miles) from Saturn.

Original Source: NASA/JPL/SSI News Release

Neptune-Sized Planet Covered in Superhot Ice

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One of the most dramatic extrasolar planetary discoveries of the year was announced this week; unfortunately, with little fanfare. Planet hunters uncovered a Neptune-sized planet orbiting a nearby star. This planet is close enough to its parent star that it’s extremely hot – above 250 degrees Celsius. And yet the intense pressure from gravity forces large quantities of liquid water into solid ice.

The planet was discovered orbiting the nearby M-dwarf star GJ 436 using the planetary transit technique. This is where a sensitive instrument called a photometer measures the periodic dimming and brightening of a star as a planet passes in front. In August 2006, astronomers captured the first hint of the planet using the Observatoire Francois-Xavier Bagnoud (OFXB) observatory in St-Luc Switzerland. It was then confirmed using the Euler 1.2m telescope at La Silla Observatory in Chile.

The announcement was made in the paper Detection of transits of the nearby hot Neptune GJ 436 b, which has been accepted for publication in the journal Astronomy and Astrophysics Letters.

With more traditional planet hunting techniques, very little information can be found about the planet, other than its mass. But planetary transits offer a wealth of data. Since the light from the star dims, and the chemical composition of the light changes, astronomers can determine the planet’s atmosphere by subtracting it from the star. They can measure both the mass, and the size of the planet, and measure the temperature of its surface.

According their calculations, GJ 436 b is approximately 50,000 km across; 4 times the radius of Earth, and approximately the size of Neptune. This makes is the smallest planet ever discovered using the planetary transit technique, and brings the possibility of uncovering Earth-sized planets tantalizingly closer. But unlike frigid Neptune, it orbits much closer than the orbit of Mercury, completing an orbit in just a few days. Even through the dwarf star it orbits is less luminous than our Sun, the planet orbits so close that it’s heated above 250 degrees Celsius. This makes it the first “hot Neptune” ever discovered.

A planet with this amount of water ice must have formed outside the star’s “snow line”, where the protoplanetary disc is cool enough for water to condense. Some process must have brought it gradually closer to the parent star, to its current position today. Once the planet got close enough to the star its outer envelope of hydrogen and helium would have evaporated away, leaving the smaller icy core.

Original Source: Arxiv

Carnival of Space #3

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The Universe Today spaceport is happy to host the third Carnival of Space. This is a roundup of cool articles about space and astronomy from bloggers and writers from across the Internet. By reading through this list of articles, we hope you’ll find some new articles to enjoy, and some new blogs to follow.

Now, let’s see who’s arrived at the spaceport…

The Space Cynics are celebrating their 1 year anniversary with a refresher course on their view of alt.space, the roadmap for space development, and why they’re so cynical.

The EarthSky Blog has this article by David S.F. Portree called Saving Spaceflight. He considers the thorny question of whether the emphasis in the space program should be on human exploration or robot probes.

When he’s not herding cats on his blog, Dynamics of Cats, Steinn Sigurdsson is writing about the launch of Corot and its first planetary discovery.

Amanda Bauer (aka the astropixie) recently spent an evening commanding the gigantic Gemini south telescope. But even that responsibility couldn’t keep her from gazing into the heavens from that Chilean peak into some of the clearest skies on Earth.

On the Physics Forums, there’s an interesting article called Andromeda Looming Large, about how the mighty Andromeda galaxy is larger than previously thought.

Chuck Magee from the Lounge of the Lab Lemming explains how Uranium Thorium star dating works. This is how they know a star can be 13.2 billion years old.

The Space Writer’s going down into an invisible ring of dark matter. Care to join?

Alan Boyle reports on his MSNBC Cosmic Log how a venture that uses outer space to generate random numbers is finally in the midst of a soft launch.

L. Riofrio from A Babe in the Universe was working on a story of how Hubble proved that the Universe was expanding and Einstein’s cosmological constant was a blunder. As the story was posted, a huge fire broke out threatening the observatory.

Emily Lakdawalla from The Planetary Society Weblog reports on how scientists have figured out that Asteroid Itokawa shakes and vibrates every time it’s hit by little rocks, and those vibrations cause Itokawa’s gravels and boulders to migrate around the asteroid’s surface and sort by size.

The Bad Astronomer Phil Plait highlights the amazing new discovery about a ring of dark matter surrounding a galaxy cluster collision, with a picture that will surely end up as your computer desktop.

Then let’s peek in with James Watt and his article about one of the many obstacles to space exploration: air.

My Astronomy Cast co-host, Dr. Pamela Gay sees a new day rising on other worlds.

And last, but not least, here’s my story on Universe Today about how you can enjoy a few extra nanoseconds of subjective time during your descent into a black hole.

Since I just can’t get enough of the Carnival of Space, I’ll be hosting it again next week. Here are your instructions to get involved for next time. I’ll see you next week.

New Technique for Finding the Mass of Black Holes

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It might sound surprising, but one of the most difficult tasks astronomers have is determining the mass of objects. It takes a binary system, where two stars or orbiting one another, to be able to make an accurate mass calculation. And determining the mass of black holes is even more difficult because they’re invisible.

But the clever astronomers have figured out a way, by measuring the location of the swirling accretion disk of material waiting to be consumed around a black hole. Since material can pile up faster than the black hole can consume it, it compresses together, heats up, and emits radiation that astronomers can detect. Researchers have discovered that there is a direct relationship between a black hole and the size of its surrounding accretion disk. Astronomers have calculated that this hot gas piles up in a location that scales up with the mass of the black hole. The more massive the black hole, the farther out the congestion occurs.

This technique has helped astronomers identify likely intermediate black holes, which contain thousand of times the mass of the Sun. Much more than a stellar mass black hole, but much less than the hundreds of millions of suns worth of mass in supermassive black holes.

Original Source: ESA News Release