Saturday, December 22, 2012

Some Facts About Space, pt 2: Stars

So here’s part two of my exciting facts-about-space blog! This time I’m going to focus on things a bit further out there: some of the really crazy stuff you may not have known about our neighboring stars.

A Neutron Star the size of a pea would weigh about as much as a small mountain.
There are many different types of stars. Neutron stars—which are actually the “leftovers” of massive stars after they go supernova—have the peculiar trait of being the most dense of all star types. Of course, Neutron Stars don’t come as small as the size of a pea, but that’s just to give you an idea of how heavy they are. Talk about a jawbreaker…

Neutron Stars have an average diameter of only 24 kilometers.
Yep, that’s a radius of only about 15 miles. In other words, the entire star would fit inside of just about any major city you’ve ever been to.

The smallest main-sequence (i.e. “normal”) star we know of is only about 20% larger than Jupiter.
It’s called OGLE-TR-122, and it’s barely big enough to even be considered a star. That poor little runt star—it doesn’t even get a proper name, just a “designation.”

The largest star we know of is bigger than the orbit of Jupiter around our sun.
It’s called NML Cygni, and it’s about 1,650 times larger than our sun. Think about it this way: we haven’t yet been able to send a human as far as Jupiter. If we lived on a planet the size of NML Cygni, it’s quite possible that we still wouldn’t even be able to travel all the way around it (like we can do relatively easily with Earth). And keep in mind: that’s the largest star we know of yet…

The oldest object in space that we know of is about 13.2 billion years old.
It’s a star called HE 1523-0901, and it lives here in our friendly neighborhood Milky Way Galaxy. To put it in perspective, the average lifespan of a star usually reaches only 10 billion years old. Also, considering that our universe is only about 13.75 billions years old, HE 1523-0901 has been around since almost the very beginning of the universe itself. But if this great-grandpa of stars wants to sit you on its lap to tell you war stories, don’t let it—though it’s smaller than our sun, it’s still a burning ball of gas and nuclear reactions, after all.

The nearest star to us is Proxima Centauri…
…but it’s still 4.24 light years from Earth. Then again, in another 26,700 years, it will have moved closer to us, and only be about 3.11 light years away. Who knows?—maybe by then we’ll have figured out a way to travel that far.

Polaris is the North Star now, but it won’t always be.
We refer to Polaris as the “North Star” because it sits almost due north from our celestial north pole. But with the way the heavens are turning, around the year 3000, it will no longer sit in that position. By then, another star named Gamma Cephei will be our new north star. Hopefully this won’t confuse our sailors too much when the time comes…

When the star Betelgeuse “dies”/goes supernova, the explosion will likely be bright enough to see in the middle of the day.
In fact, scientists believe it will be visible by naked eye in the middle of the day for the duration of several months. The unfortunate thing is that this could happen anytime within the next million years—so we probably won’t actually get to see it.

Black Holes aren’t holes.
Calling them “holes” is way off base. What we call “black holes” are actually stars. Yes, stars—like the Sun, like Polaris, like all those little dots in the night sky that we arrange into constellations.

Every star and planet has something called an “escape speed.” This is the speed that an object needs to be traveling in order to shake itself free of that star or planet’s gravity (and, therefore, be able to leave the star or planet). That said, a black hole is a star whose escape speed is faster than the speed of light. That’s why we think of them as vacuums—once something falls into a black hole’s field of gravity, it can never leave again. And that’s why they’re black—even light can’t leave the star, so it would “appear” perfectly dark.

Astronomers believe that there may be such a thing as “white holes” as well.
Though a white hole hasn’t been discovered yet, astrophysical equations imply that these oddities exist somewhere out there. As you might suspect, they act pretty much like the opposite of a black hole: rather than not allowing anything to leave their field of gravity, white holes will constantly be shedding everything from itself, to the point that nothing at all (not even light) would be able to enter the star. Talk about the ultimate extrovert…

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That’s all I’ve got for you this time around (there may or may not be a part 3 to this…). Of course there are thousands of other cool tidbits that I haven’t shared, with many more facts appearing every day. But—hey—I’ve done enough research for you already: maybe it’s time for you to do some investigating of your own. ;)


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