Earth Planet

Worried by a recent incident in which an erroneous report of a doomsday asteroid caused worldwide headlines, government scientists have begun an exercise in the ultimate spin control: How to handle news of a disaster that could destroy the planet. In a sharp departure from tradition, NASA now wants astronomers to keep news of any Earth-threatening comet or asteroid secret for 72 hours. But at least some scientists believe that the effort is doomed.

These days, it's not just finding an exoplanet. It's how you find that Earth-like body. Scientists using sophisticated telescopes and arrays can detect a planet revolving around a distant star by looking at radial velocity of the star (a faint wobble) or a “transit” of that planet across the star (a faint dimming). But no one has ever found one via “induced relativistic beaming of light” from the host star. Why would that be a big deal? It happens to be a method that relies on Albert Einstein's general theory of relativity.

MAURICE STRONG LAYS DOWN HIS FORK in the National Portrait Gallery's great hall and heads determinedly to the podium. Around him, at circular tables arranged beneath a stained-glass dome, about 80 Washington insiders, corporate executives and Bush Administration officials push back from their poulet en croute and wait politely.

NASA scientists have discovered a faraway planet that's smaller than Mercury - far tinier than they expected they could find when they launched the Kepler space telescope nearly four years ago. The hot, rocky world orbits a sun-like star that's about 210 light-years from Earth. Astronomers are excited about it because it's smaller than any planet in our solar system, said astrophysicist Thomas Barclay of NASA's Ames Research Center in Mountain View, Calif. "This is the smallest exoplanet that's ever been found," said Barclay, lead author of a report on the discovery published Wednesday in the journal Nature.

Much like earthquakes are assigned their familiar magnitude ratings, asteroids now have their own Richter scale. Planetary scientist Richard Binzel of MIT unveiled his Torino Impact Hazard Scale on Tuesday to a meeting of astronomers at Cornell University.

Researchers using a telescope at the University of Arizona said last week that they have spotted the smallest, closest asteroid ever observed. The asteroid, named 1991 BA, came within 106,000 miles of Earth on Jan. 17, said the team, which reported the sighting to the International Astronomical Union. "It was a spectacular night, not only because of world events, missiles being lofted on Israel by Iraq, but also because of cosmic events.

On a shale-covered hillside on the inaccessible northern shore of Greenland, British and Danish researchers have for the first time found intact fossils of one of the first complex animals to inhabit the Earth, a discovery that sheds new light on a crucial period of evolution that is still largely hidden by time.

From the blackness of outer space, the camera tilts downward until the rim of the planet Earth comes into view. Then from 180 miles in space Baja California rises onto the screen. This would be opening sequence of a movie filmed by astronauts aboard the space shuttle Discovery, which was scheduled to land at Edwards Air Force Base this morning.

Why is the Earth so thin-skinned? That question has troubled scientists since unmanned spacecraft revealed in the 1960s and '70s that the moon and the planet Mars have a much thicker crust than the Earth's. Now, a team of geophysicists led by Don L. Anderson of Caltech believe they have the answer.

In the 20 years since the first Earth Day, nature has proved itself to be surprisingly resilient. Witness the comeback of the American bald eagle after the banning of the pesticide DDT or the cleaning of the once-inflamed Cuyahoga River in Ohio. But the progress the world will celebrate next Sunday on Earth Day 1990 has brought little respite.

Scientists at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said Wednesday morning that an "Earth-like" planet -- that is, a small rocky planet warm enough to have liquid water on its surface and potentially capable of hosting life -- could be as close as 13 light-years away. It's hardly "next door" (as a press release touting the announcement put it), in any traditional sense: 13 light-years is something like 76 trillion miles away.  But across the vast distances of the Milky Way, said Harvard astronomer Courtney Dressing, 13 light-years amounts to "a stroll in the park.

By taking a fresh look at old data, an international team of astronomers has discovered a possible new super-Earth planet relatively nearby that could potentially hold liquid water, scientists said Wednesday. The research, released by the journal Astonomy & Astrophysics, used a novel technique to analyze existing measurements of a nearby star. The paper drew some praise even as other experts in the field eyed the results with caution. The finding adds three planet candidates around the dwarf star HD 40307 some 44 light-years away, for a total of six. (Three planets were discovered around HD 40307 in 2008.)

Scientists have spent years hunting for Earth-like planets orbiting stars elsewhere in the galaxy. Now they have found one that's a relative stone's-throw away. The so-called exoplanet - a planet beyond our solar system - is circling Alpha Centauri B, just 4.37 light-years from Earth. A mere 3.7 million miles from the star's surface, it is far too hot to support life. But there's a chance that another planetary sibling may reside in the system's so-called habitable zone, where liquid water could exist, scientists say. The discovery, described in Thursday's edition of the journal Nature, has further whet planetary scientists' appetite for finding nearby Earth-like planets - ones close enough for humans to potentially visit one day. "It's the most reasonable star to think about going to, and now we know there's a planet around it," said Nick Gautier, deputy project scientist for NASA's planet-hunting Kepler space telescope, who wasn't involved in the discovery.

Scientists have confirmed the existence of two Earth-sized, rocky planets orbiting a star called Kepler-20, 1,000 light-years away in the constellation Lyra. The planets are the smallest ever confirmed orbiting a sun-like star, and their discovery, reported Tuesday, is an important milestone for NASA's Kepler mission, which faces the technically daunting task of finding small, Earth-like worlds in faraway solar systems that may — or may not — have been able to sustain life in the past.

At least one in every four stars like the sun has planets about the size of Earth circling in very close orbits, according to the first direct measurement of the incidence of such planets, researchers said Thursday. That means that our galaxy alone, with its roughly 200 billion sun-like stars, has at least 46 billion Earth-size planets orbiting close to the stars, and perhaps billions more circling farther out in what scientists call the habitable zone, said astronomer Andrew Howard of UC Berkeley, a coauthor of a paper on the subject published in Friday's edition of the journal Science.

Scientists have discovered a planet that shouldn't exist. The finding, they say, could alter our understanding of orbital dynamics, a field considered pretty well settled since the time of astronomer Johannes Kepler 400 years ago. The planet is known as a "hot Jupiter," a gas giant orbiting the star Wasp-18, about 330 light years from Earth. The planet, Wasp-18b, is so close to the star that it completes a full orbit (its "year") in less than an Earth day, according to the research, which was published in the journal Nature.

Tradition calls for children to bend their ears this month to the folklore that Thanksgiving commemorates: a gathering of pilgrims and Indians in the fall of 1621 to offer thanks to God for a bountiful harvest. The national retelling of the story serves a purpose for adults, as well. For many, it is about the only time for reflecting, however briefly, on American Indian religion. Recently, Indian customs and religious rituals have become a topic of growing interest nationally.

Humans now consume more of the Earth's natural resources than the planet can replace, raising doubts about the long-range sustainability of modern economies, according to a new study being published in the Proceedings of the National Academy of Sciences. For the last 20 years, people have been depleting natural resources, including fish, forests and arable land, at a rapid rate.

NASA's planet-hunting spacecraft, Kepler, has made radical new discoveries about a hellish planet a thousand light years away -- proof, scientists say, that the craft will be able to carry out its mission of finding other Earths in our galaxy, provided they exist. NASA scientists released Kepler's analysis Thursday of an already known "hot Jupiter" planet called HAT-P-7b in the constellation Cygnus.

A massive bombardment of meteorites billions of years ago could have brought in enough water and carbon dioxide to jump-start the chemistry that let the Earth develop into the garden spot of our solar system. By studying meteorites and other evidence from this bombardment, a team of researchers at Imperial College in England has calculated that the meteorites could have carried in as much as 10 billion tons of water vapor and carbon dioxide to the young Earth every year for millions of years.