Radio Telescopes Resolve Pleiades Distance Debate

by Shannon Hall on August 29, 2014

An optical image of the Pleiades. Credit: NOAO / AURA / NSF

An optical image of the Pleiades. Credit: NOAO / AURA / NSF

Fall will soon be at our doorstep. But before the leaves change colors and the smell of pumpkin fills our coffee shops, the Pleiades star cluster will mark the new season with its earlier presence in the night sky.

The delicate grouping of blue stars has been a prominent sight since antiquity. But in recent years, the cluster has also been the subject of an intense debate, marking a controversy that has troubled astronomers for more than a decade.

Now, a new measurement argues that the distance to the Pleiades star cluster measured by ESA’s Hipparcos satellite is decidedly wrong and that previous measurements from ground-based telescopes had it right all along.

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Enjoy This Eye-Meltingly Awesome Photo of Our Sun

by Jason Major on August 29, 2014

Photo of the Sun captured and processed by Alan Friedman. (All rights reserved.)

Photo of the Sun captured and processed by Alan Friedman. Click for a larger version. (© Alan Friedman. All rights reserved.)

Here’s yet another glorious photo of our home star, captured and processed by New York artist and photographer Alan Friedman on August 24, 2014. Alan took the photo using his 90mm hydrogen-alpha telescope – aka “Little Big Man” –  from his backyard in Buffalo, inverted the resulting image and colorized it to create the beautiful image above. Fantastic!

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Artist concept of NASA’s Space Launch System (SLS) 70-metric-ton configuration launching to space. SLS will be the most powerful rocket ever built for deep space missions, including to an asteroid and ultimately to Mars. Credit: NASA/MSFC

Artist concept of NASA’s Space Launch System (SLS) 70-metric-ton configuration launching to space. SLS will be the most powerful rocket ever built for deep space missions, including to an asteroid and ultimately to Mars. Credit: NASA/MSFC
Story updated

After a thorough review of cost and engineering issues, NASA managers formally approved the development of the agency’s mammoth heavy lift rocket – the Space Launch System or SLS – which will be the world’s most powerful rocket ever built and is intended to take astronauts farther beyond Earth into deep space than ever before possible – to Asteroids and Mars.

The maiden test launch of the SLS is targeted for November 2018 and will be configured in its initial 70-metric-ton (77-ton) version, top NASA officials announced at a briefing for reporters on Aug. 27. [click to continue…]

Observing Neptune: A Guide to the 2014 Opposition Season

by David Dickinson on August 28, 2014

Credit

The planet Neptune as seen by the Voyager 2 spacecraft during its 1989 flyby. Credit: NASA/JPL.

Never seen Neptune? Now is a good time to try, as the outermost ice giant world reaches opposition this weekend at 14:00 Universal Time (UT) or 10:00 AM EDT on Friday, August 29th. This means that the distant world lies “opposite” to the Sun as seen from our Earthly perspective and rises to the east as the Sun sets to the west, riding high in the sky across the local meridian near midnight. [click to continue…]

Radio/optical composite of the Orion Molecular Cloud Complex showing the OMC-2/3 star-forming filament. GBT data is shown in orange. Uncommonly large dust grains there may kick-start planet formation. Credit: S. Schnee, et al.; B. Saxton, B. Kent (NRAO/AUI/NSF); We acknowledge the use of NASA's SkyView Facility located at NASA Goddard Space Flight Center.

A radio (orange) and optical composite of the Orion Molecular Cloud Complex showing the OMC-2/3 star-forming filament. Credit: S. Schnee, et al. / B. Saxton, B. Kent (NRAO/AUI/NSF)

Stars and planets form out of vast clouds of dust and gas. Small pockets in these clouds collapse under the pull of gravity. But as the pocket shrinks, it spins rapidly, with the outer region flattening into a disk.

Eventually the central pocket collapses enough that its high temperature and density allows it to ignite nuclear fusion, while in the turbulent disk, microscopic bits of dust glob together to form planets. Theories predict that a typical dust grain is similar in size to fine soot or sand.

In recent years, however, millimeter-size dust grains — 100 to 1,000 times larger than the dust grains expected — have been spotted around a few select stars and brown dwarfs, suggesting that these particles may be more abundant than previous thought. Now, observations of the Orion nebula show a new object that may also be brimming with these pebble-size grains.

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