Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.
You are here
Some galaxies are like cosmic works of art, with beautiful curves and splashes of color. Others aren’t so memorable — they look like fat, fuzzy footballs, with no features at all to set them apart. Yet these plain-looking agglomerations of stars can still be interesting — especially on the inside. Many of them — and perhaps all — contain supermassive black holes in their centers.
An example is NGC 7052. It’s almost 200 million light-years away in the constellation Vulpecula, the fox, which stands high in the south at nightfall.
NGC 7052 is one of those featureless footballs, known as an elliptical galaxy. It contains hundreds of billions of stars, but almost all of them are old and faint.
The galaxy’s center is a lot more interesting. A big doughnut-shaped cloud of dust surrounds a brilliant cluster of stars. And the stars surround a black hole that’s more than 300 million times as massive as the Sun.
The black hole itself is invisible — its gravity is so strong that not even light can escape from it. But several lines of evidence point to its existence.
For one thing, the galaxy’s core is a strong source of radio waves — the signature of matter ensnared by a strong magnetic field around a black hole. And the speed of stars and gas in the galaxy’s center show that they’re orbiting something small but extremely heavy: a black hole — an interesting feature in an otherwise dull galaxy.
More about Vulpecula tomorrow.
Script by Damond Benningfield, Copyright 2013
- ‹ Previous
- Next ›