March 21, 2008

Meanwhile, Halfway Across The Universe...

…a star exploded seven and a half billion years ago. This star died before the Earth ever existed.

Yesterday night, the light from that explosion, which literally travelled halfway across the universe, became visible on Earth Wednesday night. To the naked eye, it would have looked like a regular star, but in a place where no star should have been. But the light was seven and a half billion years old and it travelled 4,408,969,030,000,000,000,000 miles to get here without dissipating and was visible even through our atmosphere and even in an urban environment. That's 4.4 sextillion miles.

Try to imagine 4.4 sextillion of something – let’s say, jelly beans. Let’s say you could fit maybe 20 jelly beans in a container one inch by one inch by one inch. If so, 4.4 sextillion jelly beans would be 1,500 times the size of the Earth. It’s just too large a number. It only makes sense as a mathematical abstraction. The whole idea of a star, forty times the size of our sun, exploding and releasing so much power and energy as to instantly vaporize any planets that might have been around it, producing so much light that it could be seen across the entire universe, is so awesomely huge a concept that I do not think the human mind is capable of really understanding it.

Here’s something else that will really bake your noodle. The universe is about 15 billion years old. If we could see light from 15 billion light-years away, we’d be looking at the big bang. The big bang happened in a single location. But it would actually surround us and be visible from any angle in three-dimensional space. What’s more, it would appear to be equally distant no matter what perspective in three-dimensional space we used to look at it. Does that mean that the Earth is at the very center of the universe? No – if we were to magically move to any other point in the universe, like say, some planet in the Sombrero Galaxy, the light we would be seeing from 15 billion-light years away would still appear to be equidistant in all directions despite having moved nearly thirty million light years away.

The Universe is an awesomely strange place. There's so much that we're only beginning to see, much less understand. It fills me with a sense of awe and wonder.


Antonio Silva said...

hi, i noted you feel awe and wonder. Don´t you also feel fear?

Burt Likko said...

Sometimes, yes. A supernova seven and a half billion light years away does not inspire fear, though.