NASA successfully launched its Kepler planet hunting probe Friday night from California. Kepler, if all goes well, will spend at least three years focused on a small, star-rich area of the Milky Way, searching for planets similar to Earth.
Kepler will do that by looking for transits-- catching a planet moving across the disk of its parent star. To see that requires that faraway star system to be perfectly aligned with Kepler, which seems wildly unlikely. Astronomers argue, however, that the sheer number of stars in the area being studied will allow them to find many new worlds.
Transits are actually extremely useful events. Timing the transits can yield the speed of the planet, which-- using Johannes Kepler's Laws of Planetary Motion-- gives the distance of the planet from the star. That distance can tell us whether the planet is in the "habitable zone" of the star-- where life could exist. The magnitude of the dip in starlight which signals a transit is occuring tells us the size of the planet.
Sunday, March 8, 2009
Friday, March 6, 2009
Are We From Ceres?
Ceres is a body roughly 600 miles in diameter. It is the largest of a swarm of objects that orbit between Mars and Jupiter. It may have water ice, and a water ocean under the surface. And, according to scientist John Houtkopper, it may be the ultimate home of life on Earth.
Houtkopper suggests life may have developed on Ceres early in the history of the Solar System and migrated to Earth in a chunk that somehow broke off Ceres and escaped the dwarf planet's weak gravity. This is the latest version of an old theory that holds life came to Earth from somewhere else-- Mars, Venus, a comet, or another star system.
It's sort of the search for the Holy Grail for a certain group of scientists. Of course, the upshot of the basic theory keeps the origin of life a mystery by pushing that event beyond the reach of humanity, at least at present. NASA's Dawn spacecraft is scheduled to encounter Ceres in 2015. At that time, science should learn more about Ceres than it has since Ceres' discovery in 1801.
Houtkopper suggests life may have developed on Ceres early in the history of the Solar System and migrated to Earth in a chunk that somehow broke off Ceres and escaped the dwarf planet's weak gravity. This is the latest version of an old theory that holds life came to Earth from somewhere else-- Mars, Venus, a comet, or another star system.
It's sort of the search for the Holy Grail for a certain group of scientists. Of course, the upshot of the basic theory keeps the origin of life a mystery by pushing that event beyond the reach of humanity, at least at present. NASA's Dawn spacecraft is scheduled to encounter Ceres in 2015. At that time, science should learn more about Ceres than it has since Ceres' discovery in 1801.
Thursday, March 5, 2009
Discovery Moves Up
There has been another change in the launch date of space shuttle Discovery, but this time it's being moved up a day. The launch is now scheduled for March 11. The fuel valves that had delayed the launch from February 12 were finally simply replaced last week.
Discovery's main mission will be to deliver the last part of the main truss of ISS, plus the station's final pair of solar power wings.
Discovery's main mission will be to deliver the last part of the main truss of ISS, plus the station's final pair of solar power wings.
Wednesday, March 4, 2009
Another Cassini Discovery
The Cassini probe has discovered a new moon in the midst of Saturn's glorious rings. The tiny moon, too small to be resolved by Cassini's camera, is likely the source of dust for the G-ring in the ring system.
Tuesday, March 3, 2009
China On The Moon
China became the latest nation to put a spacecraft on the Moon Sunday, deliberately crashing its Changle 1 probe into the surface after it successfully completed a year long study of the Moon using a suite of sophisticated instruments.
Changle 1 was only the first step in the Chinese lunar program. Over the next few years, China plans to soft land a probe on the Moon, as well as deliver and operate a lunar rover.
Weighing in at over 5,000 pounds, Changle 1 no doubt created yet another lunar crater when it crashed into the surface.
Changle 1 was only the first step in the Chinese lunar program. Over the next few years, China plans to soft land a probe on the Moon, as well as deliver and operate a lunar rover.
Weighing in at over 5,000 pounds, Changle 1 no doubt created yet another lunar crater when it crashed into the surface.
Monday, March 2, 2009
Asteroid Flyby
An asteroid roughly 115 feet long flew past Earth this morning at a distance of about 44,000 miles. That's a close shave in cosmic terms, but astronomers had been monitoring the rock for several months and were confident there was no chance of collision.
Scientists estimate this asteroid, designated 2009 DD46, is about the same size as the body that exploded over Tunguska, Siberia, in 1908. If such a body exploded over a major city, for example, the city would be obliterated.
Asteroid 2009 DD46 is the latest reminder that Earth will be hit by a large body again unless we develop the capability to deflect such bodies into safe orbits.
Scientists estimate this asteroid, designated 2009 DD46, is about the same size as the body that exploded over Tunguska, Siberia, in 1908. If such a body exploded over a major city, for example, the city would be obliterated.
Asteroid 2009 DD46 is the latest reminder that Earth will be hit by a large body again unless we develop the capability to deflect such bodies into safe orbits.
Sunday, March 1, 2009
North Korean Satellite Launch
North Korea seems ready to attempt to launch its first satellite. That wouldn't concern the U. S.-- which is still technically in a state of war with North Korea-- except that an ability to orbit a satellite would also mean North Korea would have the ability to hit the U. S. with an ICBM. Couple that with nuclear bomb capability, and an American city could be at risk.
To counter such a threat, the U' S. is developing a missile defense system, but that program has been slow to mature, partly because of the inherent difficulty of the task, and partly because critics of the effort have resisted the concept. They argue that a fully effective missile defense is impossible to achueve, and further, that delivering a nuclear device to an American city would likely be done not atop a missile that could be traced back to its launch, but by some other means.
The Pyongyang regime, however, has not always been predictable; it has shown little inclination to act according to what others see as logical. Faced with a secretive, brutal dictator who has the ability to deliver nuclear bombs within a radius of thousands of miles, the rest of the world-- and the Obama administration-- will have an extremely tough decision to male.
To counter such a threat, the U' S. is developing a missile defense system, but that program has been slow to mature, partly because of the inherent difficulty of the task, and partly because critics of the effort have resisted the concept. They argue that a fully effective missile defense is impossible to achueve, and further, that delivering a nuclear device to an American city would likely be done not atop a missile that could be traced back to its launch, but by some other means.
The Pyongyang regime, however, has not always been predictable; it has shown little inclination to act according to what others see as logical. Faced with a secretive, brutal dictator who has the ability to deliver nuclear bombs within a radius of thousands of miles, the rest of the world-- and the Obama administration-- will have an extremely tough decision to male.
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