In space, everything is super far away. Like, really, really far. But the question is , how do scientists figure out exactly how far away things are? Well, they’ve come up with some pretty cool tricks over the years.

^{Image by Sergei Belozerov from Pixabay}

First off, there’s something called parallax (this reminds me of physics practicals back in the days, where you state that you avoided error due to parallax). Now this is a little explanation on what parallax is; imagine holding your thumb out in front of you and closing one eye, then the other. Your thumb seems to move against the background, right? That’s parallax! Scientists use this trick to measure how far away nearby stars are. They look at the stars from different spots on Earth's orbit and see how they seem to move. It's like peeking at something through a hole in a fence from two different spots—it helps you figure out how far away it is. Pretty much accurate when done this way.

But what about stuff that’s really, really far away, like galaxies? Well, that's where redshift comes in. When something moves away from us in space, its light gets stretched out and looks redder. Scientists can measure this redness to figure out how fast the galaxy is moving away from us, and therefore how far away it is. It’s like when a race car zooms by, the sound of its engine changes as it goes past you—except this time the phenomenon is with light instead of sound.

Now, let’s talk about standard candles. These aren’t your typical birthday candles—they’re stars or other objects in space that always shine with the same brightness. By comparing how bright they look from Earth to how bright they really are, scientists can figure out how far away they are. It’s like if you know how bright a flashlight is supposed to be, you can tell how far away it is by how dim it looks.

^{Image by pencil parker from Pixabay}

But what about stuff that’s really, really, really far away, like quasars? These are super bright objects at the edge of the universe. To measure their distance, scientists look at how long it takes for their light to reach us. It’s kind of like hearing an echo in a big canyon—you can tell how far away the sound came from by how long it takes to bounce back. Yeah that is one of the basic principles on which ship sonars work, echolocation and hydrophone. Only this time, the echo is being used to locate underwater objects .

Now, let’s zoom in a bit closer to home. In our own solar system, we use something called radar ranging. It’s like playing catch with radio waves! Scientists bounce radio signals off planets and asteroids and measure how long it takes for them to bounce back. By timing these bounces, they can figure out exactly how far away these objects are. Now that fascinating and I am just finding out about this myself .

Each of these methods is like a tool in a toolbox, helping scientists build a map of the universe. And when they use different tools together, it’s like double-checking their work to make sure they get it right.

^{Image by 18706286 from Pixabay}

As technology gets better, scientists can measure even farther into space. From the stars twinkling above us to the galaxies stretching out into infinity, each measurement helps us understand more about the universe.

So, figuring out how far away things are in space isn’t just about science—it’s an adventure! It’s like exploring a whole new world, except this one is millions and billions of miles away. So let’s keep looking up at the stars and dreaming about what else is out there.

• https://www.skyatnightmagazine.com/space-science/measuring-distance-space
• https://www.space.com/30417-parallax.html
• https://science.nasa.gov/solar-system/cosmic-distances/
• https://lco.global/spacebook/distance/units-distance-and-size-universe/
• https://sciencing.com/types-measurements-used-measuring-outer-space-14340.html
• https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2355164
• https://prancer.physics.louisville.edu/astrowiki/index.php/How_to_Measure_Distances_in_the_Universe
• https://www.sciencedaily.com/releases/2023/12/231215140310.htm

• First Image by Sergei Belozerov from Pixabay

• Second Image by pencil parker from Pixabay

• Third Image by 18706286 from Pixabay