Friday, October 7, 2011

Spaghettification!


Earlier this week, a second grader asked me what would happen if an astronaut fell into a black hole. "Well, what do you think might happen?" I responded back. Another anxious second grader waved his hand high. "You would get stretched out like a noodle!" he said. Very good! These second graders know more about black holes than I thought! If an astronaut were to fall into a black hole, the gravity at the persons feet would be stronger than at their head, effectively stretching their bodies as thin as spaghetti. So guess what astronomers call that effect…. Spaghettification! No joke!

Wednesday, October 5, 2011

Black Holes Don't Suck!

I'm sure you've heard of a black hole before (If you've been reading ADYK you definitely have!) But what technically is a black hole? What is it made of? What does it do? Astronomers are still a bit uncertain about all of this, but here's what we think…

 
A black hole is defined as a singularity in space. This means that it is a point in space that is infinitely small and has infinite density. It's hard to think of an object like this in real life; one that can continually gain matter but stays extremely small. Most people have the impression that black holes "suck" in all the material around them. While black holes do attract matter, they are not like vacuums in outer space. Black holes warp the space time around them into giant funnels (like the cartoon above). This causes material to orbit black holes and fall towards the center, eventually falling past the point of no return. Because black holes have acquired so much mass, they have a very strong gravitational field. It's so strong that not even light can escape their grasp. This is why astronomers call them black holes. Astronomers still have so much more to learn about these bizarre objects, and as technology improves our knowledge will approve along with it.

Monday, October 3, 2011

Saturn's Rings and Enceladus

    We all know Saturn as the big outer planet with the rings. Why does Saturn have such beautiful ring structure? Astronomers aren't entirely sure, but they must have formed back when Saturn was just an infant planet. Astronomers can, however, explain the existence of Saturn's outermost ring, the E ring. Where did this ring come from? The culprit is Saturn's Moon Enceladus!
    Above is a recent image taken by the Cassini spacecraft which is currently orbiting Saturn and its moons. As you can see, there appears to be some material erupting from the surface of the moon, and indeed there is! Enceladus experiences what we call cryovolcanism, which means that it has volcanoes which spew water and ammonia when they erupt instead of hot rocky lava. These eruptions are so intense that the material actually leaves the planet and travels into outer space! Since Saturn's rings are so close to Enceladus, the water and other molecules get caught up in Saturn's gravitational field and form the outermost ring. This ring is technically unstable, which means the material will stay for a short time, but then be lost forever into space. That's no big deal though, because Enceladus is continually erupting and adding new material to the E ring.
    Image credit: NASA/JPL-Caltech/Space Science Institute