Showing posts with label best. Show all posts
Showing posts with label best. Show all posts

Friday, November 21, 2014

Asteroid Vesta: The Best Geologic view

The new map of Vesta is a detailed geologic record of the asteroid.

Credit: NASA/JPL-Caltech/ASU

High-resolution new maps show the cratered, rocky surface of the huge asteroid Vesta in unprecedented detail, researchers say.

Images captured by NASA's Dawn spacecraft were woven together to create geologic maps of the giant asteroid Vesta.

The maps, the most detailed ones yet of of Vesta's surface features, serve as a geologic record of the asteroid that astronomers can compare to other planets and celestial bodies, researchers said.

Scientists combined 15 separate maps into one Vesta uber-map, which shows that meteorites have pummeled the asteroid since its formation about 10 million years after the birth of the solar system.

Astronomers can piece together Vesta's geologic timeline based on the sequence of meteorite impacts.


The brown colours on the map show the oldest and most heavily cratered areas on Vesta, while purple shows where Vesta was struck by two large impactors; the light purple and dark blue colors show the interior basins of the two massive impacts.

Greens and yellows show the youngest material on Vesta, which likely came from landslides or later meteorite strikes, researchers said.

A special camera onboard the Dawn spacecraft made the geologic maps possible. The camera uses seven different color filers that help analyze the different minerals covering Vesta's surface.

The photos were used to create 3D topographic models, which were then converted into maps of the surface.

It took over two years to sift through all the images and create the maps, said David Williams of Arizona State University, one of the lead scientists on the project.

The maps were published this week along with a series of papers in the journal Icarus.

Sunday, January 24, 2010

MARS is looking at its best right now

Mars, the most Earthlike planet of all the planets, has been absent from our evening sky for well over a year. Now it's coming back and here's why:

Earth and Mars are in an eternal dance with the two parties sometimes close, sometimes very far apart. Both worlds orbit the sun, with Earth doing so more quickly on the inner path. Every 2.1 years, Earth laps Mars, like a race car on the inside track. At that moment, the sun, Earth and Mars are all lined up. Astronomers call it opposition.

During much of January we've been speeding toward Mars in our orbit by an average of 3 miles per second; so Mars has been gradually getting brighter and larger in apparent size.

Mars will pass closest to the Earth at 2:01 p.m. EST during the American afternoon of Jan. 27, just two days before its Jan. 29 opposition, when it will appear to rise at sunset and set at sunrise and will be visible all night.

As a bonus, on opposition night, the Moon, just hours before officially turning full, will sit well off to the right of Mars as they climb the early evening eastern sky.