Archive for September 23rd, 2009

NASA’s Spitzer Space Telescope has seen what seems to be the early stages of planet formation. Below is an artist concept, and description.

This artist’s conception shows a lump of material in a swirling, planet-forming disk. Astronomers using NASA’s Spitzer Space Telescope found evidence that a companion to a star — either another star or a planet — could be pushing planetary material together, as illustrated here.

Planets are born out of spinning disks of gas and dust. They can carve out lanes or gaps in the disks as they grow bigger and bigger. Scientists used Spitzer’s infrared vision to study the disk around a star called LRLL 31, located about 1,000 light-years away in the IC 348 region of the constellation Perseus. Spitzer’s new infrared observations reveal that the disk has both an inner and outer gap.

What’s more, the data show that infrared light from the disk is changing over as little time as one week — a very unusual occurrence. In particular, light of different wavelengths seesawed back and forth, with short-wavelength light going up when long-wavelength light went down, and vice versa.

According to astronomers, this change could be caused by a companion to the star (illustrated as a planet in this picture). As the companion spins around, its gravity would cause the wall of the inner disk to squeeze into a lump. This lump would also spin around the star, shadowing part of the outer disk. When the bright side of the lump is on the far side of the star, and facing Earth, more infrared light at shorter wavelengths should be observed (hotter material closer to the star emits shorter wavelengths of infrared light). In addition, the shadow of the lump should cause longer-wavelength infrared light from the outer disk to decrease. The opposite would be true when the lump is in front of the star and its bright side is hidden (shorter-wavelength light would go down, and longer-wavelength light up). This is precisely what Spitzer observed.

The size of the lump and the planet have been exaggerated to better illustrate the dynamics of the system.

Image credit: NASA/JPL-Caltech

More great pictures of the HTV have been released. The first seven down another view of the HTV as its grappled by Canadaarm2 on September 17th, 2009. The last three photos are from the 18th, and show the crew entering the H-II Transfer Vehicle and the interior.

Read the rest of this entry »

Video about the Saturn equinox.

Video series from NASA that explains how space assets can help us to make better decisions in our agricultural practices.

NASA’s image of the day, details below.

Marshall Space Flight Center is testing a new robotic lunar lander test bed that will aid in the development of a new generation of multi-use landers for robotic space exploration. The test article is equipped with thrusters that guide the lander, one set of which controls the vehicle’s attitude with that directs the altitude and landing. On the test lander, an additional thruster offsets the effect of Earth’s gravity so that the other thrusters can operate as they would in a lunar environment. MSFC is partnered with John Hopkins University Applied Physics Laboratory and the Von Braun Center for Science and Innovation for this project.

Image Credit: NASA

Picture of the dust storm covering the Australia east coast taken by NASA’s Terra satellite. Props to the MODIS rapid response team.

No larger image. Credit: BBC

A wall of dust stretched from northern Queensland to the southern tip of eastern Australia on the morning of September 23, 2009, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image. The dust is thick enough that the land beneath it is not visible. The storm, the worst in 70 years, led to canceled or delayed flights, traffic problems, and health issues, reported the Australian Broadcasting Corporation (ABC) News. The concentration of particles in the air reached 15,000 micrograms per cubic meter in New South Wales during the storm, said ABC News. A normal day sees a particle concentration 10-20 micrograms per cubic meter.

Strong winds blew the dust from the interior to more populated regions along the coast. In this image, the dust rises in plumes from point sources and concentrates in a wall along the front of the storm. The large image shows that some of the point sources are agricultural fields, recognizable by their rectangular shape. Australia has suffered from a multiple-year drought, and much of the dust is coming from fields that have not been planted because of the drought, said ABC News.

NASA image by Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center. Caption by Holli Riebeek.

For an excellent ground view, two links to photos. The Big Picture is especially good.
TBP

Red Sydney