Question: how big is the galaxy
Comments
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how do know that the galaxy is that big
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Because I use research girls! Sometimes I know things, other times not. If I am not 100% sure, I look things up from places I know I can trust, and that gives me the answer. I’m a scientist, I learn all the time just like you!
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Hello girls, maybe I can help you out with your question. You asked Sam how he knows and he told you he does research. May I tell you how other scientists have figured out the size of the galaxy?
This is what I have found out:
Apparently no one really knows the exact size of the galaxy because we cannot see the edge of the galaxy. Also it has not always been the same size as it is always expanding. But scientists working at NASA in the USA have calculated the rough size using telescope that are in out of space.
These telescope provide the NASA crew with important images that they can then use to calculate the size of the universe.
With these images NASA can tell how far away a star in the galaxy is and if you know how far away it is, and if you know at what angle the star is located in comparison to the telescope then you can calculate the size.
Here is where NASA has fantastic Mathematicians helping them out.
But you and I can have a go at some of this Maths! For example, say you had a telescope and you were looking at a star in the galaxy was 100oo meters (62 miles) away from your telescope. This star fills 10 milliradians (this is the angle on the telescope). You and I can calculate the width of the galaxy like this: 100000 (62miles) * 0.01 (10 miliradians) = 1 meter (0.62 miles)So the galaxy that you and I are looking at would be 0.62 miles wide and 62miles long. 🙂 not bad! But this is a very simplified way of calculating it.
I’m not a mathematician working for NASA, I’m a microbiologist looking at superbugs but I hope it makes sense to you 🙂
girls
Hey jayfer, thanks for the question! This answer is going to know your socks off!
Our galaxy (the milky way) is 950,000,000,000,000,000 (950 quadrillion) km wide, and 9,500,000,000,000,000 (9.5 quadrillion) km thick! That’s 100,000 light years wide and 1000 light years thick!
It has about 200 billion stars!
That’s our galaxy. As for the entire universe… well it’s growing! It keeps on expanding, so it has no set size! BUT, it is known to be at least hundreds of billions of LIGHT YEARS wide (and not flat, so it has volume too!). If you think about how much bigger that is than our galaxy, and how we haven’t even reached outside our own planets around our star (let alone the other 200 billion in OUR galaxy) you sure feel small! Who knows what else is out there?
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