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Wall of gas divides
cosmic metropolis

...A new study from the Chandra X-ray Observatory unveils the star-forming factory NGC 604 as a divided neighbourhood...

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Supermassive black holes not guilty of shutting down star formation

...Galaxies cease star formation long before their supermassive black holes have the power to do the job themselves...

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C1XS takes first taste of lunar X-rays

...The UK-built C1XS instrument flying aboard the Chandrayaan-1 orbiter has successfully detected its first X-ray signature from the Moon...

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STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.

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STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.

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STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

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STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.

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Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

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Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

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Radio finds unknown molecules in space

BY KULVINDER SINGH CHADHA

ASTRONOMY NOW

Posted: 16 February, 2009

A sea change in the way radio astronomy is conducted has been responsible for finding a whole swathe of unidentified molecules in space.

Astronomers of the National Radio Astronomy Observatory used the Robert C. Byrd radio telescope at Green Bank, West Virginia, to find 720 spectral lines. “About 240 of those are from unknown molecules,” says Dr Anthony Remijan. As a comparison, only 150 molecules have been identified by astronomers over the past 40 years, including sugars, alcohols, and PCAs (a group of chemicals found in burnt toast).


Remijan and his colleagues are part of the Prebiotic Interstellar Molecule Survey (PRIMOS), which is a project studying a star-forming region near the Milky Way’s centre. “We're making available to all scientists the best collection of data below 50-gigahertz ever produced for the study of interstellar chemistry,” Remijan says proudly.

Click to enlarge. The chemical cycle of stars and planets was discussed at the ‘Cosmic Cradle of Life’ symposium in Chicago. Image: Bill Saxton, NRAO/AUI/NSF.

Beforehand, astronomers would often decide what molecule(s) they would want to find, and then search a narrow band of radio wavelengths for their signature. Instead, what Remijan’s team have done is search a broad range of wavelengths and made this data available for scientists to explore and study. This brings radio astronomy spectroscopy more in line with what’s done in other wavelength regions, such as the infrared and optical. The reason that this hasn’t happened before is, as Remijan says, “We have not had a telescope with the frequency coverage and sensitivity available to conduct this type of survey. The completion of the Robert C. Byrd Telescope provided the first real opportunity to attempt this type of survey.”


So have any of the molecules been identified yet? “To date, no. We are still working on compiling the frequencies and intensities of these unknown transitions which will help with the later identification of these species.” Amusingly however, Remijan describes how certain unwanted features ‘jump out’ of the spectra, “At the low frequencies we are observing that the major features are not astronomical at all! In fact they are interference from ground based transmitters and satellites broadcasting in the same frequency band.”

Remijan goes on to say how transmissions from satellites such as XM and Sirius mask any weak spectral features from large molecules in those particular ranges, making them hard to identify. “That’s another reason why we are doing the survey though, to identify these roadblocks to our investigation.” This is of importance as large molecules are the precursors of biological activity and identifying them in large numbers should tells us where we should be looking for life.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
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Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
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3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
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