Did you like how we did? Rate your experience!

Rated 4.5 out of 5 stars by our customers 561

Award-winning PDF software

review-platform review-platform review-platform review-platform review-platform

Video instructions and help with filling out and completing What Form 2220 Ting

Instructions and Help about What Form 2220 Ting

Light is the fastest thing we know. It's so fast that we measure enormous distances by how long it takes for light to travel them. In one year, light travels about six trillion miles, a distance we call one light year. To give you an idea of just how far this is, the moon, which took the Apollo astronauts four days to reach, is only one light second from Earth. Meanwhile, the nearest star beyond our own Sun is Proxima Centauri, 4.2 light years away. Our Milky Way is on the order of a hundred thousand light years across, and the nearest galaxy to our own, Andromeda, is about 2.5 million light years away. Space is mind-blowingly vast. But wait, how do we know how far away stars and galaxies are? After all, when we look at the sky, we have a flat, two-dimensional view. If you point your finger to one star, you can't tell how far this star is. So how do astrophysicists figure that out? For objects that are very close by, we can use a concept called trigonometric parallax. The idea is pretty simple. Let's do an experiment. Stick out your thumb and close your left eye. Now open your left eye and close your right eye. It will look like your thumb has moved, while more distant background objects have remained in place. The same concept applies when we look at the stars. But distant stars are much, much farther away than the length of your arm, and the Earth isn't very large. So even if you had different telescopes across the equator, you would not see much of a shift in position. Instead, we look at the change in the star's apparent location over six months, the halfway point of the Earth's year-long orbit...