Articles on universe since 2000 (contd.)

13 New Planets Spotted

Astronomers have announced the discovery of 13 new planets among the stars, including one inhabiting a solar system similar to our own. The newcomers bring the tally of planets found orbiting stars outside the solar system to more than 90.

They include one Jupiter-like planet orbiting a Sun-like star at the same distance as the Jovian giant is from the Sun in our system. The team, led by US planet-finding pioneers Geoffrey Marcy and Paul Butler, also announced the discovery of the smallest extrasolar planet ever detected - a world with a mass 15 per cent that of Jupiter and 40 times larger than the Earth.

The newfound planet orbits at about 5.5 times the Earth-Sun distance (5.5 astronomical units, or AU), which is comparable to the 512 million gap between Jupiter and the Sun.

It is between 3.5 and five times the mass of Jupiter, and its slightly elongated orbit takes it around the star in about 13 years - quite close to Jupiter's orbital period of 11.86 years.

Unveiling the Infrared Sky

Your home computer can become a portal to a wonderland of stars, thanks to a massive release of images from an infrared sky survey sponsored by NASA and the National Science Foundation. Astronomers have released 1.9 million new images of stars and galaxies gathered by the Two-Micron All Sky Survey (2MASS), the most thorough census of stars ever made. The 1.9 million images will fill 6,000 CD-ROMs, equivalent to 4,000 gigabytes or four terabytes of computer hard disk space. In order to cover the entire sky, the 2MASS survey uses two highly automated, 1.3-metre diameter telescopes, one at Mount Hopkins, Arizona, the other at the National Science Foundation's Cerro Tololo Inter-American Observatory, Chile. Operations for 2MASS began in 1997 and its catalogue will contain more than 300 million objects by the time observations are concluded in 2001. Already, 2MASS data has uncovered numerous stars with characteristics so unique that astronomers had to revise a century-old classification system of known types of stars. Astronomers armed with 2MASS data have discovered previously unknown star clusters within, and galaxies beyond, our Milky Way.

Meteorites in Northern Lights

Every year, the Perseids meteors that hit Earth are most impressive around the shower's peak. This year the bright nearly-full Moon threatened to outshine all but the brightest meteors. A geomagnetic storm, however, triggered dazzling aurora (Northern Lights) during the peak of the 2000 Perseid shower. An interplanetary shock wave from the Sun struck Earth's magnetosphere just before the peak, triggering the powerful storm because of which there was a brilliant sky show over Western Europe and North America. Bright red, green and blue curtains and fountains of light poured out and filled the skies till dawn. Meteors and auroras occur in different layers of our atmosphere. Perseid meteoroids burn up in the mesosphere, a zone that extends from approximately 50 to 90 km altitude. The lowest fringes of the aurora are at least 70 km high, and can extend to 1,000 km above out planet. Only astronauts can fly through the aurora! You can enjoy images if the shower at Science @NASA.

Meteorite found in Oman is from Mars

A dark, baseball-size rock found in the deserts of Oman is the latest confirmed meteorite from Mars, said University of Tennessee geologist Dr Larry Taylor. Only about 14 Martian meteorites have been found, and this one- found by private rock hunters in West Asia in February, taken to Russia, then brought here for analysis - is only the third located in a desert region. Most of the other meteorites were discovered at the South Pole, including the rock known as Allen Hills 84001 that some researchers suggested in 1996 contained fossilized remains of extraterrestrial life.

Black Holes put on weight

Astronomers at the Universities of Nottingham and Birmingham in the UK have obtained the first direct evidence that the massive black holes at the centers of galaxies put on weight as they get older by eating gas and stars. It has been known for a number of years that the centers of almost all galaxies contain small, very massive, black holes. Such a super massive black hole can weigh in excess of a billion times the mass of our Sun, yet may occupy a region not much larger than our solar system. Little is known about how they came to be at the centers of all galaxies. It may be that they were there before the galaxies formed around them, or have they grown over time by sucking in some of the stars and gas from their host galaxies. It appears that these black holes have built up to their current stature by acquiring mass over the entire lifetime of the galaxies that they live in, with no signs that this growth has come to an end.

Ulysses spacecraft catches biggest comet tail

A CHANCE encounter between the spacecraft Ulysses and the wake of a speeding comet has helped scientists to identify the longest comet tail every recorded.

The discovery by two independent teams of scientists, reported in the science journal Nature on Wednesday, could open up a new way of studying the heavenly bodies that astronomers believe may hold the secrets of our solar system. "This tail extends more than half a billion kilometers (300 million miles). That's more than three times the distance from the earth to the sun. It's just unbelievable," Nathan Schwadron, of the University of Michigan's College of Engineering, said.

The scientists knew something strange had occurred on May 2, 1996, when Ulysses, the spacecraft launched in 1990 by NASA and the European Space Agency to study solar winds, radioed data back to Earth.

Everything went haywire for a few hours. The solar winds, a stream of particles flowing from the Sun, went calm. The spacecraft was then bombarded by charged particles from what turned out to be the wake, or ionized vapor tail, of what scientists calculated could only be comet Hyakutake, which was in another part of the solar system.

The encounter was amazing because the tail of the comet turned out to be much bigger than astronomers expected. It was also only the fourth time a spacecraft had crossed paths with a comet tail, giving scientists an opportunity to identify chemicals in the wake. "It brings up a whole new way to study comets, and I think opens up a whole new area of science," Schwadron said.

If scientists had better data for instruments designed to intercept long tails of comet dust, Schwadron and his colleagues in Michigan had researchers at the International Space Science Institute in Switzerland believe it would be possible to learn how stars have processed material over time. It could also help to answer cosmic questions such as the age of the universe and how it was formed. "Finding and identifying the comet's tail is only the beginning. Now we can learn a great deal more about what conditions are like in comet tails by studying data from instruments that have actually been there," said Geraint Jones, of Imperial College in London, who reported the finding of the comet tail in a separate study in Nature. Jones and researchers at Queen Mary and Westfield College in London said the tail is 570 million km long. It is also only the fourth comet tail encountered by a spacecraft and the one furthest from the Sun.

Beam me to Mars, Scotty

NASA plans to launch a $300 million roving robot to Mars in 2003 to search for the water that many researchers suspect flows just beneath the surface of the arid planet, space agency officials announced Thursday.

In a sharp departure from its recent practice, the Jet Propulsion Laboratory will build the Mars spacecraft on its own in Pasadena, Calif., rather than in partnership with Lockheed Martin Space Systems Co. in Denver, which built several Mars probes that failed last year.

National Aeronautics and Space Administration officials are still mulling over whether to launch a second $150 million robot rover mission to Mars in 2003.

"We are evaluating the implications of a two-rover option," said Edward Weiler, NASA's associate administrator of the office of Space Science in Washington, D.C. "I intend to make a decision in the next few weeks so that, if the decision is to proceed with two rovers, we can meet the development schedule for a 2003 launch."

The rolling robot will be dropped to the surface of Mars in a cocoon of airbags, using a landing system that proved its worth during the 1997 Mars Pathfinder mission - the most successful U.S. Mars mission since the Viking landings of the 1970s. Mission planners abandoned the more complex rocket-powered landing system that caused the Mars Polar Lander to crash last year.

NASA's new Mars rover will be almost 10 times larger than the Sojourner robot that landed with Pathfinder and carry five instruments to study the surface of the red planet during its 90-day mission, JPL officials said Thursday. It could travel as much as a half mile from its landing site.

"This one will rove as much in one day as Sojourner roved in its entire 90-day mission," said JPL. Mars program manager Firouz Naderi. "In essence this is a robotic geologist."

The mission is scheduled to be launched in late May 2003 on a Delta II rocket and reach Mars on Jan. 20, 2004, after a 7 1/2-month cruise. When it enters the Martian atmosphere, an international flotilla of at least four other spacecraft also will be orbiting the red planet.