Astronomy Picture of the Day 01-18-04

Explanation: Make your background the closest image of Mars yet. The Spirit Rover currently rolling on Mars has taken the highest resolution image to date of another planet. The above black and white image spans only about 1.5 centimeters across, with details smaller than 1/10 of a millimeter visible. A microscope attached to the Spirit rover's instrument arm took the image. Up close, the Martian soil appears to planetary geologists to have clumping properties similar to cocoa powder. As more images come in and as the Spirit Rover continues to explore Mars, more information about the unusual floor of Gusev Crater are likely to emerge.

That soil looks like a salt flat, maybe Epsom salts (magnesium sulfate). Hmmmmm....

Stormy cloud of star birth glows in new Spitzer image
NASA/JPL NEWS RELEASE
Posted: January 15, 2004

NASA/JPL-Caltech/Cornell University and University of Leiden
Download a larger version of image here

A dusty stellar nursery shines brightly in a new image from NASA's Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility. Spitzer's heat-sensing "infrared eyes" have pierced the veiled core of the Tarantula Nebula to provide an unprecedented peek at massive newborn stars.

"We can now see the details of what's going on inside this active star-forming region," said Dr. Bernhard Brandl, principal investigator for the latest observations and an astronomer at both Cornell University, Ithaca, N.Y., and the University of Leiden, the Netherlands.

Launched on August 25, 2003, from Cape Canaveral Air Force Station, Florida, the Spitzer Space Telescope is the fourth of NASA's Great Observatories, a program that also includes Compton Gamma Ray Observatory, the Chandra X-ray Observatory and the Hubble Space Telescope. Spitzer's state-of-the-art infrared detectors can sense the infrared radiation, or heat, from the farthest, coldest and dustiest objects in the universe.

One such dusty object is the Tarantula Nebula. Located in the southern constellation of Dorado, in a nearby galaxy called the Large Magellanic Cloud, this glowing cloud of gas and dust is one of the most dynamic star-forming regions in our local group of galaxies. It harbors some of the most massive stars in the universe, up to 100 times more massive than our own Sun, and is the only nebula outside our galaxy visible to the naked eye.

While other telescopes have highlighted the nebula's spidery filaments and its star-studded core, none was capable of fully penetrating its dust-enshrouded pockets of younger stars.

The new Spitzer image shows, for the first time, a more complete picture of this huge stellar nursery, including previously hidden stars. The image also captures in stunning detail a hollow cavity around the stars, where intense radiation has blown away cosmic dust.

"You can see a hole in the cloud as if a giant hair dryer blew away all the gas and dust," said Brandl.

By studying this portrait of a family of stars, astronomers can piece together how stars in general, including those like our Sun, form.

JPL manages the Spitzer Space Telescope mission for NASA's Office of Space Science, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech.

[From a BBC report of 1/16/04:]

'Magic' surface

The "cakey" surface of Mars at Spirit's landing site has intrigued scientists ever since they saw the first images showing how the rover's landing bags had pleated the surface as they dragged over it.

It has become known as the "magic carpet" of Mars.

"There is probably some cohesive component keeping the soil particles together," said Bob Sullivan, a member of the science team. Researchers want to know if the adhesion is the result of electrostatic forces or some other process.

One tantalising theory is that the carpet may contain sticky salts created when water evaporated through the upper layer of soil.

"The other instruments on the arm will test these hypotheses," said Sullivan.

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