Category: Astronomy

The crews of space shuttle Endeavour and the International Space Station have been busy during the current mission and here’s a few pictures and a video to update what’s been happening. Early Sunday, Mission Specialists Rick Linnehan and Mike Foreman completed the second spacewalk of five scheduled for STS-123. The two spacewalkers assembled Dextre, the final element of the International Space Station’s Mobile Servicing System, attaching two arms to the robot-like tool designed for station maintenance and service. Above is a picture of Linnehan during the first spacewalk. He’s anchored to the Canadarm2 mobile foot restraint as it moves him into position for a construction task. Isn’t that something we’d all like to do….be out in space and pretend to be flying? This image is the embodiment of the human spirit.

Here’s an image from the second spacewalk, with the two astronauts working on constructing the stick-figure like Dextre. With its two arms, Dextre will remove and replace smaller components on the Station’s exterior. It will be equipped with lights, video equipment, a tool platform and four tool holders. Each of the arms are 11 feet long and have seven different joints.

Dextre can perform dexterous tasks, and can sense forces and movements of objects it is manipulating, and can automatically compensate its movements to ensure the payload is manipulated smoothly. Dextre will be used to load and unload objects, use robotic tools, attach and detach covers and install various units of the Space Station.

The other important task for this mission is attaching the Japanese Logistics Module’s Pressurized Section (JLP), the first component of the Japan’s Kibo laboratory. This is an image from NASA TV showing Japanese astronaut Takao Doi as he and Expedition 16 Commander Peggy Whitson open up the module and go inside for the first time.

Astronaut Garrett Reisman, Expedition 16 flight engineer works during the first spacewalk of the mission. Among other tasks, he and Linnehan prepared the Japanese logistics module for removal from Space Shuttle Endeavour’s payload bay and installed equipment on Dextre.

NASA astronauts Greg Johnson (foreground), STS-123 pilot; and Bob Behnken, mission specialist, work the controls of the station’s robotic Canadarm2 in the Destiny laboratory of the International Space Station while Space Shuttle Endeavour is docked with the station. European Space Agency (ESA) astronaut Leopold Eyharts, mission specialist, looks on.

Wake-up calls are a long-standing tradition of the NASA program. Each day during the mission, flight controllers in the Mission Control Center will greet the crew with an appropriate musical interlude. This video from flight day 4 gives us chance to get to know Garrett Reisman (aka Mr. Saturday Night) who will stay on board the ISS for 6 months.

Four centuries after Galileo Galilei was ordered by the Catholic Church to come to Rome and stand trial on suspicion of heresy, a statue of the Italian astronomer will be erected at the Vatican. 2009 is the International Year of Astronomy, which celebrates 400 years since Galileo first used a telescope to study the heavens, and the Vatican plans to join in commemorating the anniversary. Galileo was condemned to house arrest by the Catholic Church in 1633 because his belief that the sun was at the center of the solar system, and not the Earth, contradicted the bible.

The statue was commissioned by the Pontifical Academy of Sciences and was paid for with private donations. The president of the Academy, Nicola Cabibbo, said the statue shows Galileo standing and gesturing as if he were teaching. Cabibbo, a particle scientist, said honoring Galileo in this way is important because the Academy considers Galileo to be one of the oldest members of their group. Galileo was a member of the National Academy of Lincei, from which the Pontifical Academy began.

At his trial, Galileo argued that his heliocentric beliefs and writings did not oppose the church’s teachings, and stated that the bible was not meant to provide scientific explanations. He once wrote that scripture does not reveal what is in the heavens, but rather how to get to heaven.

In 1992, Pope John Paul II acknowledged that that the church made a mistake when it condemned Galileo for maintaining that the Earth revolved around the sun. At that time the church officially conceded that the Earth was not stationary. The pope also said that theologians should keep informed on scientific advances to determine if there would be cause for “introducing changes in their teaching.”

The exact location for the statue has not yet been determined, but Cabibbo was confident that the details would be worked out in time for the start of the anniversary celebrations in early 2009.

Original News Source: The Catholic Times

Not much to say, just a pretty picture of supernova remnant N132D, captured by NASA’s Chandra X-Ray Observatory. I don’t know about you, but this actually reminds me of a mysterious creature that might pass by a deep sea submersible. But nope, it’s in space, located in the Large Magellanic Cloud. In fact, it’s the brightest supernova remnant in the nearby dwarf galaxy.

As usual, an image like this is completely false colour, based on different wavelengths of X-ray radiation. The low energy X-rays are in red, the intermediate in green and the high-energy rays are in blue.

N132D may be the brightest supernova remnant, but it’s actually part of a rare class of oxygen-rich explosions. Astronomers are still trying to understand what conditions existed in the star itself to generate an explosion that spread so much heavy elements, like oxygen, into the surrounding space.

Original Source: Chandra News Release

OK, I think I have my feet back on the ground now. But I may have gotten lost in the Small Magellanic Cloud’s Open Star Cluster. I’ve just been playing around with Google Sky, and have traveled around the universe, seeing dramatic astronomical images as never before. Anyone interested in astronomy, or those of you who just like awe-inspiring images will enjoy Google Sky. Just like Google Earth, Google Sky allows you to search for specific locations, zoom in and out of images, and pan around areas to look at nearby features. But Google Sky teams up with some of the largest ground- and space-based astronomical surveys to allow you to explore the far reaches of the universe.

You can select from the thumbnail images at the bottom of the display to bring up planets, constellations, highlights from the Hubble Space Telescope, famous stars, galaxies and nebulae, and views of the universe in the x-ray, ultraviolet and infrared. There’s also podcasts about upcoming astronomical events, and plenty of information about the images, including direct links to the Hubble’s comprehensive website about the specific image you are viewing.

What I found most interesting is the infrared images, particularly the ones from Spitzer. Initially, you see them in the visible spectrum, but then it quickly changes to infrared. Being able to compare the two spectrums is one of my favorite aspects of Google Sky. And other features allow you to play with the transparency to blend between all the different wavelengths and see how different parts of the universe light up at different wavelengths.

There’s also a view of the microwave sky from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), which shows the universe as it was 380,000 years after the big bang.

Also very interesting is the “Historical” feature, seeing the sky as drawn by Giovanni Maria Cassini (printed in 1792) showing the constellations in their classical form.

You can also use Google Sky to observe your own view of the sky, and zoom in for a closer look.

Start gallivanting around the universe with Google Sky here.

It’s amazing to think that the Sun and planets formed out of a diffuse cloud of gas and dust. Somehow, the dust clung together into larger and larger particles – grains of sand. This sand then went on to become pebbles, rocks, and eventually entire planets. Well now astronomers have discovered a young star system with a disk of sand-sized particles orbiting it.

The discovery was made by Christopher Johns-Krull, assistant professor of physics and astronomy at Rice University, working with collaborators in the US, Germany, and Uzbekistan.

Astronomers have detected microscopic dust particles orbiting other stars before, but only by sensing their infrared emissions. This method isn’t precise enough to tell astronomers how big these particles become, or how far they’re orbiting from the newly forming star.

In this new study, the researchers measured the light reflected from sand orbiting a binary system called KH-15D. The stars are about 2,400 light years from Earth in the Cone nebula, and they’re a mere 3 million years old.

The researchers discovered that the Earth has a nearly edge-on view of KH-15D. From our point of view, the dusty disk mostly blocks the stars from view, but one star has an eccentric orbit that occasionally peeks up above the disk.

“We were attracted to this system because it appears bright and dim at different times, which is odd. These eclipses let us study the system with the star there and with the star effectively not there,” Johns-Krull said. “It’s a very fortuitous arrangement because when the star is there all the time, it’s so bright that we can’t see the sand.”

The team examined 12 years of data gathered by a handful of observatories around the world, and studied how light from the star was being reflected by the disk. They were able to determine the chemical composition and size of the sand-like particles.

Original Source: Rice University News Release

Despite the name, a “planetary nebula” has nothing to do with planets. They were given the confusing name 300 years ago by William Herschel because they looked like planets in their early, rudimentary telescopes. They’re really the glowing shells of gas and dust puffed out by stars nearing the end of their lives. But wait, planets might be responsible after all.

And as a special bonus for actually reading this article, I’ll treat you to a gallery of beautiful planetary nebulae.

Astronomers at the University of Rochester have announced that low-mass stars, and maybe even super-Jupiter-sized planets might actually be responsible for the beautiful puffy nebulae. Their research appears in the latest editions of the Astrophysical Journal Letters and Monthly Notices of the Royal Astronomical Society.

Most medium-sized stars, like our own Sun, will end their lives as planetary nebulae. Even though the star has lived for billions of years, this stage just lasts several tens of thousands of years. The star runs out of fuel, its core contracts, and it ejects the outermost layers of its atmosphere into space. The expanding shell can be spherical in shape, but its often twisted and elongated.

Astronomers used to think that powerful magnetic forces shape the nebula. But maybe the low-mass companion star or super-Jupiter planet might be providing the gravity that warps and distorts the shape of the nebula.

The Rochester team studied the interplay between a companion star or planet and the expanding envelope of material given off by a dying star. When the star or planet is in a very wide orbit, its gravity drags some of the envelope material around on its orbit. This creates spiral waves of nebula material that expand out from the star, bunched up by interactions with the star or planet.

There could be an entirely different effect when the companion orbits within the envelope of the dying star. It could spin up material more quickly, ejecting it into a large disk around the star. It might also work with the star’s magnetic field to force material into jets out the poles.

Of course, a companion orbiting too close to the parent star might get shredded into a debris disk orbiting the dying star. And this disk could interfere with the nice smooth expansion of stellar material.

It might be that companion stars and large planets might be responsible for the beautiful shapes we see.

Planets might be needed for planetary nebulae after all.

Original Source: University of Rochester News Release

The venerable Cassini spacecraft will make an extremely close flyby of Saturn’s moon Enceladus, one of the most intriguing moons in the Saturn system. Earlier flybys by Cassini revealed a geyser-like plume of ice particles shooting up from Enceladus’ south pole region. This means there’s a water source on the moon, and of course, water on another body in our solar system is an intriguing mystery that we want to take a closer look at. And this look will be extremely close. At one point during the flyby, when Cassini is near the equator of Enceladus, the spacecraft will only be about 50 km from the moon’s surface.

Cassini will skim over moon on March 12, at 19:06 UT. When Cassini is near the south pole, however, the spacecraft will be about 200km from Enceladus’ surface– which is probably a good thing. Even a small particle hitting the spacecraft could do a lot of damage, and the scientists say Cassini should be flying well above where any ice particles should be.

Learn more about the flyby in this video that the Jet Propulsion Laboratory put together.

Also, this graphic shows the areas on Enceladus that will be observable to Cassini as it whizzes by. Cassini’s scientists are hoping this flyby will help us understand the interior of this moon and how extensive its water source may be.

Original News Source: Cassini website