How can we measure distance and size of space bodies?

Question

How do we know the distance and size of the sun for instance? I assume it's not geometry as you must be given the distance to get the size?

Also what about other stars, nebula or galaxies? How do we know their size and distance? How do we know that they're not bigger and further away, or smaller and closer to us?

Answer 1

ok, its oretty complicated!

http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question39.html

i suggest you look at the website...very good explanation

my physics professor used in a lecture, very good.

Answer 2

You know how if you look at something you get a sense of how far away it is? That's because you are looking at it with TWO eyes. This 'binocular' vision lets you get a sense of depth. So if you take a picture of a distant body in the summer, and then compare it to a picture you took of the same thing in the winter, the earth is on the other side of the sun and you can use parallax to figure out how far away it is.

parallax : –noun 1. the apparent displacement of an observed object due to a change in the position of the observer.
2. Astronomy. the apparent angular displacement of a celestial body due to its being observed from the surface instead of from the center of the earth (diurnal parallax or geocentric parallax) or due to its being observed from the earth instead of from the sun (annual parallax or heliocentric parallax). Compare parallactic ellipse.
3. the difference between the view of an object as seen through the picture-taking lens of a camera and the view as seen through a separate viewfinder.
4. an apparent change in the position of cross hairs as viewed through a telescope, when the focusing is imperfect.

Answer 3

As far as the sun is concerned, one way to measure it is geometry. You know the angular size, you know the period of the earth, you have Keplers laws, can get it's size fairly easily with that info.

For further objects you mainly use luminosity. You make assumptions about how luminous stars of certain sizes are.

You can also measure their composition and refine your models some. Run some computer simulations and you got an answer.

Answer 4

Weather balloons were launched in the 1950s

Answer 5

Easy! The difference between your head and your planet , YOUR ANUS, is about the same distance as the store where you can purchase a tee-shirt, you moron!

Answer 6

Do you remember doing algebra in school?

Answer 7

Put your darn shirt on!

Answer 8

with a very very very very very very very etc etc.. long ruler

Answer 9

try here:http://rds.yahoo.com/_ylt=A0oGkmbzZA1GvnMBeiFXNyoA;_ylu=X3oDMTE3ZzhhZnVuBGNvbG8DdwRsA1dTMQRwb3MDNARzZWMDc3IEdnRpZANGODI0XzE0MA--/SIG=12lbvui7f/EXP=1175369331/**http%3a//en.allexperts.com/q/Astronomy-1360/Distance-Size-Stars.htm