How do astronomers find planets around distant stars? If you look at a star through binoculars or a telescope, you’ll quickly notice how bright the star is, and how difficult it is to see anything other than the star, especially a small planet that doesn’t generate any light of its own! Astronomers look for a shift, or wobble, of the star as it gets gravitationally “yanked” around by the orbiting planets. By measuring this wobble, astronomers can estimate the size and distance of larger orbiting objects.
Doppler spectroscopy is one way astronomers find planets around distant stars. If you recall the lesson where we created our own solar system in a computer simulation, you remember how the star could be influenced by a smaller planet enough to have a tiny orbit of its own. This tiny orbit is what astronomers are trying to detect with this method.
Materials
- Several bouncy balls of different sizes and weights, soft enough to stab with a toothpick
- Toothpicks
Yes, you are correct! I neglected to update the other part of the answer when I corrected the 0.33m part. Thanks for catching that! I’ve updated the file as well.
If d1 = .33
and d1 + d2 = R = 2
Then shouldn’t d2=1.67m? (the answer sheet says .67)
I feel like I’m missing something.
Oh no! Looks like I have a typo… because how can it possibly be 3.33m away on a 2m rod? I’ll get the download fixed. My apologies! Thanks for your eagle eye!!
I just realized I may have confused you towards the end of my calculations. The “m” & “kg” are the units for the values and not variables. Sorry!
I can’t seem to match your answer to problem 1 in the worksheet. Please, help. Below is my work:
What we know:
m1 = 10kg, m2 = 2kg, R = 2m, d1 = ?
m1d1=m2d2
d1 + d2 = R -> d2 = R – d1
My work:
m1d1=m2d2
m1d1=m2(R-d1)
m1d1=m2R-m2d1
m1d1 + m2d1 = m2R
d1(m1+m2) = m2R
d1 = (m2R) / (m1 + m2) = ((2kg)(2m)) / ((10kg) + (2kg)) = 4m/12 = 0.33m <- My answer
Your answer = 3.33m