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Starry Science: Measure Astronomical Distances Using Parallax

An astronomy-related activity from Science Buddies

Observations and results
As the near object moved farther from the observation points, did the apparent movement of the object decrease (as measured from the left and right observation points)?
When a relatively distant object is viewed from two different points, it appears to move less compared with a relatively nearby object. Similarly, in this activity you should have seen that as the "near object" (the table with the rock, yardstick and rubber band on it) got closer to the "distant object" (the tree, light pole, etcetera), it appeared to move less (when you compared its apparent position between the left and right "observation points" inside the Hula-Hoops). It might have been hard to tell the difference for the first two measurements, but the relationship should have become clearer after that point.
Because the apparent movement of an object (the parallax) depends on how far the object is from the observation points, astronomers can figure out how far away relatively nearby stars are. This is done by looking at a nearby star's apparent movement relative to distant stars when they are all viewed from different observation points (that is, from different points in Earth's orbit around the sun).
More to explore
A Puzzling Parallax, from Science Buddies
Parallax, from
Parallax—Greek Astronomy for Kids, from History for Kids
Parallax, from StarChild

This activity brought to you in partnership with Science Buddies

Science Buddies

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