Nearest Black Hole

New measurements show that the nearest black hole to Earth is only about half as far away as previously thought. Don't worry, though. There's still about 7,800 light years between it and us. That's a huge distance, even for something as powerful as a black hole.

Of course, our current search techniques aren't perfect, and the various objects in the galaxy are in constant motion, so there's no guarantee astronomers will never find a black hole closer to us than the current record holder. However, the Earth has been around for 4.5 billion years or so, and there's no reason to think it won't be around, orbiting a life sustaining Sun, for a very long time to come.

Black holes are not things to worry about, in any case. Time and energy and worry are best directed at matters that can be altered by human effort-- curing disease, ending wars, grappling with widespread poverty. If a black hole did have Earth in its crosshairs, there's absolutely nothing we could do about it. Not now, and not for thousands or perhaps millions of years.

ALH84001

In 1996, a team of NASA researchers made big news by announcing they had found evidence for life on Mars in a meteor that had come from Mars. The meteor had been the first found in 1984 in the Allen Hills of Antarctica, and had been labeled ALH84001.

The claim was controversial. Many scientists argued the tiny structures inside the rock the NASA team saw as fossils could have non-biological explanations. Supporters of the life theory often conceded that point, but argued the most likely explanation was life.

After a decade of intensive study of Mars by numerous spacecraft designed to pursue numerous approaches to data-gathering, the case for life on Mars-- either in the past or currently existing-- is far from clinched. However, an argument for a warmer, wetter Mars early in its history-- and perhaps fairly recently-- seems to be strengthening. That Mars, of course, would have been more conducive to life.

Using better tools and more knowledge than were available in 1996, a team at NASA's Johnson Space Center in Houston, which, it should be noted, included the key members of the 1996 team, has reexamined the meteor. The 2009 conclusion? The most likely explanation of the structures in the rock is Martian life.

Dragon To ISS

SpaceX's cargo capsule Dragon is scheduled to make the first of three demonstration flights to ISS between May and November next year. During that time three astronauts who have worked with Dragon will be aboard ISS if all goes as planned, and the company has said the first Dragon flight will take place when an astronaut familiar with the vehicle is on board the space station.

That's more important than it may seem at first blush. Dragon will not dock with the station. Instead, like Japan's cargo ship, Dragon will simply fly close enough to ISS for a robotic arm, operated by an astronaut, to grab it and bring it into the station.

SpaceX's Falcon 9 launcher will carry Dragon to space, and the first flight of that configuration is scheduled for early next year. After the three demonstration flights, SpaceX already has a contract with NASA to fly 12 cargo flights to ISS through 2015. That contract is worth $1.6 billion. The company is also working on man-rating both Falcon 9 and Dragon so that the company could ferry crews between Earth and low Earth orbit.

Iapetus Explained

For over 300 years, astronomers have known there was something odd about Saturn's moon, Iapetus. The leading hemisphere is much darker than the trailing. Recent images taken by the Cassini spacecraft confirm the leading explanation of the contrast.

As Iapetus orbits Saturn, dust-- perhaps from other moons, perhaps from Saturn's rings-- falls onto the leading hemisphere. Dust is much darker than ice, hence that hemisphere has become darker. Reinforcing the process, the layers of dust slightly warms the surface, which allows water vapor to migrate to the trailing hemisphere, where it freezes back into ice. The small size of Iapetus-- about 900 miles in diameter-- and, therefore, its low gravity also aids the migration of the water vapor, further supporting the entire process.

Spirit Wheel Problem

NASA's Mars rovers each have six wheels. Opportunity, after nearly six years on the planet, continues to roll right along.

Spirit, however, has had more problems. It has been functioning without an operating right front wheel since 2006, and for the past several months has been stuck in deep sand. During NASA's recent attempts to extricate Spirit, the right rear wheel has stopped spinning, perhaps permanently. The rovers were designed to function on four wheels if necessary-- three, if the right three-- but NASA isn't sure Spirit can get out of its current predicament with two dead wheels.

A time factor is also beginning to loom. Winter at Spirit's location on Mars begins in May 2010. Given the precise way the rover is situated, NASA doesn't believe it could gather enough solar energy to survive the winter. So, the fight to save Spirit might be reduced to a simple imperative. Move or die. In six months.

Saturn's Hexagon

One of the most bizarre things yet found in the Solar System is the hexagon of clouds that extends deep into Saturn's atmosphere directly over the planet's north pole. For the past several years, the area has been in darkness during Saturn's northern winter, but it is now emerging into light, and Cassini is taking the best pictures yet of the formation.

A jetstream of wind surrounds the formation, seeming to hold it together. Coming off each of the six corners is a wave of wind. Exactly how those features explain the formation is completely unclear at the moment, but the hexagon has been there for at least thirty years, so scientists will probably have plenty of time to puzzle it out.

Getting MRO Back

NASA's Mars Reconnaissance Orbiter has been out of the data gathering business since August, when it put its main computer in safe mode. The craft had also had computer problems in February and June, so when the August event occurred JPL engineers decided to do a thorough study of MRO's software.

That study completed, JPL started uploading software fixes to the probe a couple weeks ago, and engineers hope to be getting data from MRO again by next week. That would be a big plus for Mars science. MRO is the most powerful of the probes currently orbiting Mars, and even with its computer problems has sent back more data about the planet than all other Mars probes combined.