Friday, September 13, 2013

Voyager Reaches the Final Frontier

Courtesy NASA/JPL
Click to enlarge
This artist's concept puts solar system distances in perspective. The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance. One AU is the distance from the sun to the Earth, which is about 93 million miles or 150 million kilometers. Neptune, the most distant planet from the sun, is about 30 AU.
Informally, the term "solar system" is often used to mean the space out to the last planet. Scientific consensus, however, says the solar system goes out to the Oort Cloud, the source of the comets that swing by our sun on long time scales. Beyond the outer edge of the Oort Cloud, the gravity of other stars begins to dominate that of the sun.
The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU from our sun. The outer edge is estimated to be around 100,000 AU.
NASA's Voyager 1, humankind's most distant spacecraft, is around 125 AU. Scientists believe it entered interstellar space, or the space between stars, on Aug. 25, 2012. Much of interstellar space is actually inside our solar system. It will take about 300 years for Voyager 1 to reach the inner edge of the Oort Cloud and possibly about 30,000 years to fly beyond it.
Alpha Centauri is currently the closest star to our solar system. But, in 40,000 years, Voyager 1 will be closer to the star AC +79 3888 than to our own sun. AC +79 3888 is actually traveling faster toward Voyager 1 than the spacecraft is traveling toward it.
The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory, in Pasadena, Calif. Caltech manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.

So...did Voyager 1 leave the Solar System? Astronomer Phil Plait shares his thoughts:

Here are some more great links about Voyager 1's interstellar journey.

What does Interstellar space sound like? Click here.

For those who want to like to get technical, here is a paper about the sudden loss of Cosmic Rays back in August 2012.

From the Twitter of William Shatner!

Click to Enlarge

Tuesday, September 10, 2013

Super Earth Gliese 1214b Might Hold Water

Might this distant planet hold water? Actually, given how close Gliese 1214b is to its parent star, any water, if it exists, would surely be in the form of steam. In theabove artist's illustration, the super-Earth Gliese 1214b is imagined passing in front of its parent star, creating a mini-eclipse that alerted humanity to its presence. Gliese 1214b, also designated GJ 1214b, has been designated a super-Earth because it is larger than the Earth but smaller a planet likeNeptune. The entire Gliese 1214 planetary system is of the closest known systems to our Sun, located only 42 light years away. The parent star, Gliese 1214 is a slightly smaller and cooler version of our Sun.Recent observations from the Subaru telescope in Hawaii found very littlescattering of blue light from the parent star by the planet. This appears most consistent with a planet that has a watery atmosphere -- although it is still possible that the super-Earth has clouds so thick that little of any color of light was scattered. Detecting water on exoplanets is important partly because most lifeforms on Earth need water to survive.