Giant Black Holes

Category: Philosophy

Even Bigger Stuff

When black holes were theorized in the 1960s many astronomers pooh-poohed them as impossible.


A black hole, it was theorized, was a star that exploded in a supernova at the end of its life cycle, then collapsed into a super-dense mass from which nothing could escape.


They were called black holes because, to a telescope, they would appear as a hole in space from which not even light could escape.

These masses would then continue to grow by absorbing mass from around them - anything that came into their gravitational reach.


Many others said, that while theoretically possible, black holes would never exceed the size of a pinhead, and that their event horizons - the limit where nothing can escape them, not even light - their event horizons couldn't be larger than Earth's moon.

Since that time we've launched magnificent telescopes into space, and now have a view of the Universe that is greater than anything man imagined possible 50 years ago.

We've not only discovered numerous black holes, proving the theory correct, we've also found that they can be much larger than the size of Earth's moon. Much larger.


Today's exercise in visualizing and feeling really big things is the discovery of a really, REALLY Big Black Hole.

The picture below shows the immense size of a black hole discovered in the galaxy NGC 3842. NGC 3842, shown in the background image, is the brightest galaxy in a rich cluster of galaxies.

The black hole is at its center and is surrounded by stars, as shown in the central figure.


This black hole is seven times larger than Pluto's orbit.


Our solar system (inset at bottom right) would be dwarfed by it. (Photo credit: NOAO)

Click on the photo for a larger image.

Learn more:


Mind boggling, isn't it? I mean, I sat and pondered (meditated) about this for an hour.

Seven times larger than the orbit of Pluto?!?!?!?! I mean, come on!


Putting it in perspective:

Light travels at a bit over 186,000 miles per second and can speed around the Earth 8.5 times in a second.

Light takes about 8 minutes 19 seconds to travel from the Sun to Earth.

Pluto has an elliptical orbit, staying 3 to 4.5 billion miles away from the Sun.

Light takes over five hours, on average, to reach Pluto from the Sun.

This Black Hole has an event horizon seven times larger than that. Its total diameter is 70 light-hours - three light-days - across.


So much for the belief that Black Holes would be tiny!


Study on this and try to wrap you head around it, because in the next exercise we're going to look at something Even Bigger.


Dr. Jim


P.S. For entertainment value, here are some more images of giant black holes:

Here's a 25 minute documentary on super massive black holes. It has some great photos and animations:

Dr. Jim

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