Messenger has found new and “compelling” evidence that there is water ice locked in the permanently shadowed craters of Mercury.

Messenger has found new and “compelling” evidence that there is water ice locked in the permanently shadowed craters of Mercury.

On Monday I had spoken to one of the project scientists for this discovery, David Lawrence, in connection with an article I am doing for Astronomy on the evidence of water on the Moon. I knew the Mercury announcement was coming, and asked him for some details. Based on what he told me, it struck me that the evidence for water on Mercury is actually more conclusive than the evidence for the Moon. (In fact, inconclusive nature of the lunar data is the point of my Astronomy article, based on previous posts here and here on Behind The Black.

The more intriguing aspect of this discovery on Mercury, however, is the unknown dark material that covers and protects some of this water ice. That some scientists believe it might even be organic material deposited there by comets and asteroids is most interesting.

Impressive radar images of near-Earth asteroid 2007 PA8 were taken during its recent fly-by of Earth.

Impressive radar images of near-Earth asteroid 2007 PA8 were taken during its recent fly-by of Earth.

The images … reveal possible craters, boulders, an irregular, asymmetric shape, and very slow rotation. The asteroid measures approximately one mile wide (about 1.6 kilometers).

The asteroid poses no threat to Earth. The resolution of the images, however, is astonishing, especially considering it was done by radar.

A house-sized asteroid will zip past the Earth in February at a distance less than 14,000 miles.

Chicken Little report: A house-sized asteroid will zip past the Earth in February at a distance less than 14,000 miles.

The asteroid, referred to as 2012 DA14, has a diameter of approximately 45m and an estimated mass of 130,000 tonnes. It was discovered at the start of 2012 and is set to travel between the Earth and our geostationary communication satellites on 15 February 2013. At a distance of just 22,500km this will be the closest asteroid ‘fly by’ in recorded history. Asteroid and comet researchers will be gathering at the University of Central Florida (UCF) in Orlando, U.S., to watch the event, but experts say there is no chance of a collision – this time.

The claim that this is the closest “fly by” in recorded history sounds bogus to me, but because of the size of this asteroid the fly-by will nonetheless be quite interesting. Scientists should be able to get a very good look at 2012 DA14 as it goes by.

The science team for New Horizons is considering shifting the spacecraft’s Pluto flyby away from the planet to avoid orbital debris.

The science team for New Horizons is considering shifting the spacecraft’s Pluto flyby away from the planet to avoid orbital debris.

“We’ve found more and more moons orbiting near Pluto — the count is now up to five,” Stern said. “And we’ve come to appreciate that those moons, as well as others not yet discovered, act as debris generators populating the Pluto system with shards from collisions between those moons and small Kuiper Belt objects.”

Telescopes of the future

Two stories were published on Thursday about two very different future space telescopes. Both are worthwhile, but the differences between them illustrate how the industry of space astronomy — like manned space — is evolving from Big Science and government to small, efficient, and privately built.

First there is this story describing how the nonprofit B612 Foundation’s project to launch an infrared telescope by 2017 had passed its first technical review.
» Read more

Deep Impact fired its engines today to adjust its orbit, giving it the option of visiting a near Earth asteroid in the future.

Deep Impact fired its engines today to adjust its orbit, giving it the option of visiting a near Earth asteroid in the future.

The press release is very vague about this future mission. I suspect there is a question of funding, which means that even if they can go to the asteroid, they might not have the funds to staff the mission.

The mysterious dark streaks on Vesta

dark material on Vesta

In a preprint paper published today at the Los Alamos astro-ph website, scientists have taken a detailed look at the mysterious dark streaks seen by Dawn on the surface of the asteroid Vesta and have concluded that the material comes from impacts, not from volcanic activity.

The scientists also concluded that

the majority of the spectra of [dark material] are similar to carbonaceous chondrite meteorites mixed with materials indigenous to Vesta.

Carbonaceous chondrite meteorites are considered to be the most primeval material in the solar system. This means that Vesta has the potential to give scientists a convenient laboratory for studying that primeval material and the early formation of the solar system. Ideally, the best way to do this would of course be to go there.

The scientists also theorize that much of this material was brought to Vesta by a single large impact.
» Read more

One of Dawn’s reaction wheels, used to orient the spacecraft, shut down last week.

Uh-oh: One of Dawn’s reaction wheels, used to orient the spacecraft, shut down last week.

During a planned communications pass on Aug. 9, the team learned that the reaction wheel had been powered off. Telemetry data from the spacecraft suggest the wheel developed excessive friction, similar to the experience with another Dawn reaction wheel in June 2010. The Dawn team demonstrated during the cruise to Vesta in 2011 that, if necessary, they could complete the cruise to Ceres without the use of reaction wheels.

That the spacecraft can get to Ceres without reaction wheels is good. However, can it be oriented precisely to do science without these wheels? The JPL press release does not say.

Dawn has begun its slow departure from Vesta in anticipation of its journey to the solar system’s largest asteroid, Ceres.

Dawn has begun its slow departure from Vesta in anticipation of its journey to the solar system’s largest asteroid, Ceres.

The departure was actually announced two weeks ago, but since this is a very slow process it isn’t like we have missed anything. Dawn’s ion engines are very efficient, but they work at a very leisurely pace. It will take a month for the engine’s thrusters to push Dawn out of its orbit around Vesta.

1 23 24 25 26 27 31