Orphan Planets?

Orphan planets? What a sad thought. A planet all alone floating through space, no "parent" star and no "brother or sister" planets in a nice "home" of a solar system. For a long time astronomers didn't think many orphan planets existed, but new research suggests that Orphan planets may be even more common than stars! (There's 400+ BILLION stars in just our galaxy!) 

 

Artist's conception of an orphan planet

Orphan planets, or planets in general outside our solar system, are not something we can point a telescope at and directly observe. Astronomers have to get crafty and find other ways of detecting these bodies. To find normal planets, astronomers watch a star for a long time, and if they see a periodic dimming of the star then they assume there is a planet orbiting around it (even though we can't directly see the planet.) Finding orphan planets is a bit more difficult though, because these planets are dark and cold and not orbiting a star. We can, however, use a trick I've discussed before, called gravitational lensing, to find such planets. Long story short, if you have a planet floating through space, lets say 20 light years away, and it passes in front of a cluster of stars say 100 light years behind it, instead of dimming the stars, the planet will bend the stars light around it and the cluster will actually look brighter! So if we suddenly see a short brightening of a star cluster, or other distant object, and there is no real explanation for it, an orphan planet may have crossed our path. Astronomers have just announced the discovery of 10 Jupiter sized orphan planets ~15,000 light years away!

Where did these orphan planets come from? The leading theory is that they formed around a star with other planets, but were kicked out of the system soon after forming by gravitational forces of the host star and other planets. So they're pretty much planet rejects that are given up at birth and become orphan…. Wow that's dark. I promise the next post will have a happier vibe to it!

Image credit: NASA/JPL-Caltech

Volcanism On Io

 

Io, one of the Galilean moons of Jupiter, is the most volcanically active body in our solar system. Its surface is littered with volcanoes that produce 100 times more lava each year than those n Earth do. Many of the circular shaped plateaus in the image above are volcanoes, and the dark one just left of center is currently erupting! Io does not have tectonic plates like that crack or get forced upward and cause volcanoes like Earth does. Instead, Io's volcanoes are formed because Jupiter tugs and squeezes the moon as it orbits. It squeezes so hard that the surface essentially pops like a zit and spews out lava (gross!).

Until recently, astronomers were unsure exactly where the magma was coming from. The magma could have originated at the very center of the moon, just under the surface, or anywhere in between. Astronomers used magnetic field data from the Galileo mission (a satellite that orbited Jupiter from 1995-2003) to discover that the magma sits just under Io's surface. The only way that Io could have produced the strange magnetic field signature observed by Galileo is if it has liquid ultramafic rocks directly below the surface. Ultramafic rocks are special rocks that when in liquid form can conduct high amounts of electricity. Earth's mantle is thought to contain a lot of these types of rocks. This magma ocean on Io is probably over 2200 degrees F! I sure wouldn't want to live anywhere near one of those volcanoes!

Image Credit: Galileo/JPL/NASA