all geo astronomy stories

Sulfur dioxide may have helped maintain a warm early Mars

404132862 — Thu, 20 Dec 2007 12:56:35 -0500

Sulfur dioxide (SO2) may have played a key role in the climate and geochemistry of early Mars, geoscientists at Harvard University and the Massachusetts Institute of Technology (MIT) suggest in the Dec. 21 issue of the journal Science. Their hypothesis may resolve longstanding questions about evidence that the climate of the Red Planet was once much warmer than it is today.

Oceans are back on Mars

Mon, 09 Jul 2007 13:40:25 -0400

Since spacecraft sent back the first close-up images of Mars more than 30 years ago, some experts have insisted that oceans once existed on the now dry, cold planet. Critics have maintained for decades that such an idea is the product of unrestrained imaginations. Now, a study published in the June 14 issue of the British journal Nature reports new evidence that our neighbor in space once boasted an ocean or oceans as big, relative to planet size, as the Atlantic on Earth. "We were able to lay to rest one of the main objections to the idea that there once were oceans on Mars," says Taylor Perron, a postdoctoral fellow in Harvard's Department of Earth and Planetary Sciences.

Astronomers nab culprit in galactic hit-and-run

70652986 — Mon, 26 Mar 2007 05:46:46 -0400

The Andromeda galaxy, the closest large spiral to the Milky Way, appears calm and tranquil as it wheels through space. But appearances can be deceiving. Astronomers have new evidence that Andromeda was involved in a violent head-on collision with the neighboring dwarf galaxy Messier 32 (M32) more than 200 million years ago.

"Like a CSI team, we gathered clues and reconstructed the scene of the crime," said Pauline Barmby (Harvard-Smithsonian Center for Astrophysics), a member of the research group that made the discovery. "The evidence clearly shows that M32 is guilty of committing a hit-and-run."

This discovery was reported in the Oct. 19, 2006, issue of the journal Nature.

Dramatic proof of the galactic smash-up came from images taken by the Infrared Array Camera (IRAC) on NASA's Spitzer Space Telescope. Those images revealed a never-before-seen dust ring deep within the Andromeda galaxy. When combined with a previously observed outer ring, the presence of both dust rings suggests a long-ago disturbance whose effects are still expanding outward through Andromeda.

Strange new planet baffles astronomers

70652986 — Mon, 26 Mar 2007 06:28:15 -0400

Using a network of small automated telescopes known as HAT, Smithsonian astronomers have discovered a planet unlike any other known world. This new planet, designated HAT-P-1, orbits one member of a pair of distant stars 450 light-years away in the constellation Lacerta.

"We could be looking at an entirely new class of planets," said Gaspar Bakos, a Hubble fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). Bakos designed and built the HAT network and is lead author of a paper submitted to the Astrophysical Journal describing the discovery. That paper is available online at http://arxiv.org/abs/astro-ph/0609369.

With a radius about 1.38 times Jupiter's, HAT-P-1 is the largest known planet. In spite of its huge size, its mass is only half that of Jupiter.

"This planet is about one-quarter the density of water," Bakos said. "In other words, it's lighter than a giant ball of cork! Just like Saturn, it would float in a bathtub if you could find a tub big enough to hold it, but it would float almost three times higher."

HAT-P-1 revolves around its host star every 4.5 days in an orbit one-twentieth of the distance from Earth to the Sun. Once each orbit, it passes in front of its parent star, causing the star to appear fainter by about 1.5 percent for more than two hours, after which the star returns to its previous brightness.

HAT-P-1's parent star is one member of a double-star system called ADS 16402 and is visible in binoculars. The two stars are separated by about 1500 times the Earth-Sun distance. The stars are similar to the Sun but slightly younger - about 3.6 billion years old compared to the Sun's age of 4.5 billion years.

Major funding for HATnet was provided by NASA.

Alien treasures in our backyard

70652986 — Mon, 26 Mar 2007 05:36:05 -0400

Astronomers have gained an important clue to guide their hunt for extrasolar worlds. And that clue points to the unlikeliest of places -- our own backyard. "It's possible that some of the objects in our solar system actually formed around another star," says astronomer Scott Kenyon (Smithsonian Astrophysical Observatory). How did these adopted worlds join our solar family? They arrived through an interstellar trade that took place more than 4 billion years ago when a wayward star brushed past our solar system. According to calculations made by Kenyon and astronomer Benjamin Bromley (University of Utah) and published in the Dec. 2, 2004, Nature, the Sun's gravity plucked asteroid-sized objects from the visiting star. At the same time, the star pulled material from the outer reaches of our solar system into its grasp. "There may not have been an equal exchange, but there was certainly an exchange," says Bromley. Kenyon and Bromley reached this surprising conclusion while working to explain the mystery object Sedna, a world almost as large as Pluto but located much farther from the Sun. Sedna's discovery in 2003 puzzled astronomers because of its unusual orbit - a 10,000-year-long oval whose closest approach to the Sun is well beyond the orbit of Neptune.

New moons found around Neptune

70652986 — Mon, 26 Mar 2007 05:26:48 -0400

Astronomers have discovered three new moons of Neptune, boosting the number of known satellites of the gas giant to 11. These moons are the first to be discovered orbiting Neptune since the Voyager II flyby in 1989, and the first discovered from a ground-based telescope since 1949. It now appears that each member of the giant planet's irregular satellite population is the result of an ancient collision between a former moon and a passing comet or asteroid. "These collisional encounters result in the ejection of parts of the original parent moon and the production of families of satellites. Those families are exactly what we're finding," said JJ Kavelaars of the National Research Council of Canada, one of the team leaders along with Matthew Holman of the Harvard-Smithsonian Center for Astrophysics.

Atmosphere detected on distant world orbiting another star

70652986 — Mon, 26 Mar 2007 05:16:28 -0400

One-hundred-and-fifty light years away from Earth, in the constellation Pegasus, is a star known as HD 209458. Using NASA's Hubble Space Telescope, a research team was able to detect the atmosphere of a planet orbiting the star. This marks the first time that scientists were able to observe the atmosphere of a planet outside our solar system. They also were able to get information about its chemical composition. The astronomers were not looking specifically for gases that would be found in a life-sustaining atmosphere, since it's not probable that a planet as hot as the one observed would contain life. But they think their technique can be used to look at other planets' atmospheres, which could provide the first direct evidence for life beyond Earth. The discovery was made by David Charbonneau of the California Institute of Technology and the Harvard-Smithsonian Center for Astrophysics, Timothy Brown of the National Center for Atmospheric Research, Robert Noyes of the Harvard-Smithsonian Center for Astrophysics, and Ronald Gilliland of the Space Telescope Science Institute.

Stellar apocalypse yields first evidence of water-bearing worlds beyond our solar system

70652986 — Mon, 26 Mar 2007 05:14:51 -0400

The first evidence that planetary systems beyond our own contain water, a molecule that is an essential ingredient for known forms of life, was discovered recently by using the Submillimeter Wave Astronomy Satellite (SWAS), a small radio observatory that NASA launched into space in December 1998. The discovery was reported in an article published in the journal Nature on July 12, 2001. "Over the past two years, SWAS has detected water vapor from a wide variety of astronomical sources," says Gary Melnick of the Harvard-Smithsonian Center for Astrophysics, principal investigator on the SWAS mission. "What makes the results we are reporting today so unusual is that we have found a cloud of water vapor around a star where we would not ordinarily have expected to find water."

21 moons 'swarm' planet Uranus

70652986 — Mon, 26 Mar 2007 05:03:45 -0400

In 1999 three new moons were discovered orbiting Uranus, a great gasball of a planet about 2 billion miles from Earth. The discovery raised the number of Uranian moons to 21, the most, as far as is known, in the skies of any planet. Researchers believe the moons were "captured" billions of years ago. "We were excited to find these newest satellites," says Matthew Holman, an astronomer at the Harvard-Smithsonian Center for Astrophysics. "We think they are cometlike objects captured by Uranus when the solar system was billions of years younger." The evidence for such capture is in the strange orbits of the moons. Most moons circle the mother planet in the same plane as planets circle the sun, called the ecliptic plane. Uranus boasts 16 moons that move this way.