What's Up for July 2011?

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What's Up for July: Asteroids. Hello and welcome! I'm Jane Houston Jones at NASA's Jet Propulsion Laboratory in Pasadena, California. Asteroids are scraps of the original building material of our solar system.

So they tell us about our own origins.

After the planets formed, residual material remained.

Bits of dust and rock bumped into each other, sometimes sticking together and sometimes scattering.

Most asteroids orbit the sun between Mars and Jupiter in a region known as the asteroid belt.

This month NASA's Dawn mission, which launched in 2007, arrives at the asteroid Vesta, the first of two objects it'll explore.

Dawn will study the conditions and processes of the solar system's earliest time.

And Vesta and Ceres are the right two bodies to study.

Vesta is an asteroid and Ceres is a dwarf planet, like Pluto.

Vesta and Ceres reside in the boundary area of the asteroid belt, where the composition of bodies changes
from being almost dry to showing the effects of hydration.

Scientists believe Vesta is very dry, while Ceres may have a layer of water-ice or even liquid water beneath its crust.

Dawn will study the roles of water -- and size -- in determining the evolution of the planets.
The spacecraft will orbit Vesta for a year.

Next July it'll depart for the dwarf planet Ceres, arriving in February of 2015.

You can see Vesta yourself this month and next. It'll be a little brighter in August.

It's the only asteroid bright enough to see with your unaided eye, because of its high albedo.

Albedo refers to how well an object reflects light.

Ceres, though larger than Vesta, is farther away and not as bright.

You can easily spot Ceres in your telescopes next month.

Check out the Dawn mission's Vesta Fiesta event page and find a viewing event near you. Or host a Vesta viewing event yourself.

You can read all about asteroids at solar system dot nasa dot gov slash yss, for Year of the Solar System.

You can learn all about NASA's missions at www dot nasa dot gov.

That's all for this month. I'm Jane Houston Jones.

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