Mars was too salty to sustain life for much of its history, new evidence from the Opportunity rover on the Martian surface indicates. Minerals deposited in sedimentary rocks suggest they formed in extremely salty water -? even saltier than oceans on Earth. Such conditions would have made it inhospitable to even the toughest micro-organisms.
Venus is much like planet Earth its composition, but also very different in other ways -- it's bone-dry with little sign of water, experiences temperatures hot enough to melt lead, is enshrouded in a thick poisonous atmosphere of CO2 and sulfuric acid, and even rotates "backwards." Now we may have an explanation for this weirdness ?- a tremendous head-on collision of two bodies may have formed our planetary neighbor.
Gravitational lenses are like giant magnifying glasses in the sky. They occur where huge accumulations of matter, like galaxy clusters, create enough gravity to warp and magnify the light of objects beyond them. This enables us to see objects normally too far away to be viewed by even the most powerful telescopes. Gravitational lenses were once thought to be rare. But astronomers using Hubble have found several, and new sky surveys found more. Scientists are now training a "digital robot" to find additional lenses.
A mission to the Moon will search for water. Scientists would like to know if the Moon does have residual water, as hinted at by earlier missions. The Lunar Crater Observation and Sensing Satellite will send an impactor into a dark crater at the Moon's south pole. Instruments will measure the plume produced by the impact to see what materials are present, looking particularly for water. LCROSS will launch in October 2008 and the impact will take place early in 2009.
Stars were recently found forming in a long tail of gas trailing away from a galaxy. We normally would not expect to see stars being born so far from their parent galaxy. Scientists believe the pressure of the galaxy's motion through space as it plummeted toward the center of a huge cluster of galaxies stripped away the gas that formed these "orphan stars."
Gravitational lensing is highly useful quirk of the universe. When vast amounts of matter accumulate -- as in enormous clusters of galaxies -- the intense gravity created distorts and magnifies the light of objects behind the cluster. The effect is like creating a giant magnifying glass in space. Astronomers recently used the effect to find one of the youngest galaxies ever seen, and track the placement of dark matter.
NASA has a full launch schedule coming up, with something being launched nearly every month. Astronauts will make four shuttle flights to the International Space Station, as well as a critical trip to Hubble to make repairs and add new instruments to the telescope. NASA will also provide the vehicle for lifting new science spacecraft into orbit, in addition to a few military launches. Finally, in 2009, NASA will launch the Kepler mission, meant to find Earth-sized planets around other stars.
Get ready for a total eclipse of the Moon on Feb. 20. Eclipses of the Moon only happen when the full Moon passes through the shadow cast by our planet. This eclipse is visible for most of North America, all of South America, western Europe and western Africa.
Mercury, the closest planet to the sun, is hard to observe from Earth. We know a little about it from the Mariner 10 spacecraft that flew by Mercury in 1974, but a large part of the planet was never mapped. Messenger, launched in 2004, recently reached Mercury, taking color pictures and probing the planet's mysterious magnetic field.
Cosmic rays consist of high-energy particles that streak through space, crashing into the Earth's atmosphere and leaving a tell-tale trail. But where do these rays come from? Experiments have turned up different results. One shows the rays originate from somewhere in the nearby universe, while another suggests the rays are left over from the Big Bang. A new experiment may help answer the question.
In 1908, a tremendous explosion rocked a sparsely populated region of Siberia, destroying hundreds of square miles of forest. The destruction was likely caused by an asteroid colliding with Earth. Now new computer simulations point toward a smaller asteroid than was previously thought. That smaller asteroids could cause such devastation is an eye-opener for astronomers who look to protect Earth from inevitable future collisions.
What a headache! New findings from examination of mammoth tusks and bison skull remains suggest that 30,000 to 40,000 years ago a meteorite shower peppered the Alaska region with pellets. Amazingly some of the animals may have survived this event, although they were probably severely injured. The individual who found these tusks, Allen West, later searched through over 15,000 artifacts to find the micrometeorites imbedded in some of the tusks and bones. With help from Lawrence Berkeley Lab, they were able to determine when the event happened. Is this one of the explanation for other large animal extinctions?
An asteroid 164 feet wide could be on a collision course with Mars. The asteroid is expected to cross Mars' orbit later this month and may come as close as 30,000 miles to Mars. Astronomers calculate a one-in-20 chance of the asteroid actually striking the red planet.
The Orion Nebula is 300 light-years closer to Earth than previously thought. Radio telescopes have obtained the most precise measure ever of distance to this giant star-forming region. Because the distance to the Nebula is shorter than expected, the stars in the nebula must also be less bright than we believed, and thus older.
Dying red giant stars may zoom out of position as they expire. The stars may eject their mass mainly in one direction, causing the star to move in the opposite direction. Comet Holmes continues to defy understanding, shielding its secrets with a cloud of bright dust. And we bring you a special report on dark energy from the Space Telescope Science Institute.
Sometimes those serene, rounded elliptical galaxies harbor much deeper and more interesting structures. In Hubble Space Telescope observations, one elliptical galaxy shows shells-shaped groups of stars that probably originated in a violent collision between galaxies. The material from the merger is feeding a supermassive black hole in the galaxy's center, creating a quasar that emits enough energy to be seen across the universe.
We've found planets beyond our solar system, but nothing Earth sized. Still, astronomers are considering what such a world might look like. Computer models provide ideas of 14 different theoretical planet types, to help planet hunters spot telltale indicators. Researchers hope that the models will provide information about planet composition and similar characteristics when astronomers begin finding Earth-sized planets.
Want to win a quick $30M? Just finance and successfully land a robotic mission on the moon! The X Prize Foundation and Google have combined to offer a prize for a lunar lander to rove around, take pictures and video and send data back to us on Earth. The foundation and Google expect private companies from around the world to compete for the prize and the achievement. About 347 inquiries have already been made!
A tiny galactic neighbor to the Milky Way, Canis Major Dwarf, was discovered in 2003. The galaxy, 25,000 light years away from our solar system, is being torn apart by the gravity of the Milky Way as it orbits our galaxy. It was detected because it has a large number of red giant stars, detectable by the Two Micron All Sky Survey, which views the sky in infrared.
Astronomers search for stars similar to the Sun in order to understand how the Sun formed and if it is unique. So far, the stars we've found that are like the Sun have had notable differences. The closest candidate was analyzed recently and found to have a composition that strongly resembles our Sun. The research gives us ideas about the nuclear fusion processes that take place in the cores of Sun-like stars and clues about the formation of planetary systems.