Posts Tagged ‘orbit’

MESSENGER Orbits Mercury

Posted by Petra on 18th March 2011 in Exogeology, Petra's Blog

MESSENGER was inserted into orbit around Mercury yesterday, March 17th. Launched on August 13th, 2004, MESSENGER has been in interplanetary flight for over six and a half years! I bet that after this long waiting, the MESSENGER team is thrilled to finally be in orbit. As for me, I think visiting Mercury ROCKS!

MESSENGER is a NASA Mercury orbiter. It’s name is an acronym for MErcury Surface, Space ENvironment, GEochemistry, and Ranging. One of its goals is to learn about the topography of Mercury’s surface, and another is to find out the composition of its atmosphere.

On its way to Mercury, MESSENGER has had one Earth flyby, two Venus flybys, and three Mercury flybys. In one of these Mercury flybys, volcanism on the surface and water in the exosphere were discovered. Also on the way to Mercury, MESSENGER took this ROCKIN’ “family portrait” of our Solar System:

There’s a lot about Mercury we’ve found because of MESSENGER. For example, could you imagine seeing a whole side of a planet which you’ve never seen before? MESSENGER gave us just that in this picture:

The instruments on board will be turned on and checked on the 23rd of March, and on the 4th of April the mission’s primary science phase begins. I look forward to seeing what new discoveries are made about our amazing innermost planet!

Exogeology ROCKS!

-Petra Stone

Is Pluto a Planet?

Posted by Petra on 1st April 2010 in Petra's Blog

I figured this would make an appropriate April Fool’s Day post… :)

Whether Pluto is a planet or not is a topic that’s had a lot of controversy since the term “planet” was defined. According to the new definition, a planet must: (1) orbit the Sun, (2) be basically round, and (3) have “cleared the neighborhood” around its orbit. Pluto fits all the requirements except for having cleared the area. Since it’s not a satellite of something else, it’s now considered a dwarf planet.

Pluto has been considered a planet for long enough now though that many people are upset by reclassifying Pluto as a dwarf planet.

I wonder if getting a better idea of what Pluto is like will help settle the debate? The New Horizons probe’s mission is planned to explore the Kuiper Belt and Pluto. It’s scheduled to arrive on July 14, 2015, making a flyby. That’s pretty soon considering how long of a mission it is to get there! I can’t wait to find out what it sees. Meanwhile, the Hubble Space Telescope got some good photographs of Pluto changing seasons, and New Horizons made a flyby of Jupiter.

What do I think? I believe that dwarf planets should be considered a specific type of planet, like terrestrial planets and gas giants. They should be considered just as important as any other planets. But there’s a good reason for changing the definition of “planet”; there are so many dwarf planets still being discovered that the number of planets in the Solar System would be hard to keep track of. Besides, we need a way to distinguish between planets and asteroids, and dwarf planets are somewhere in between. No matter what the definition of planet is though, Pluto is still an important member of the Solar System.