Space Speed

478 viewsOtherPlanetary Science

So, a car against asphalt it’s pretty easy determinining the speed.
But when someone says a spaceship, for example Voyager, travels at about 61.5 kkm/h. What speed are we comparing against? According to Google, Earth rotates at the equator at about 1.5 kkm/h. So if we said that we compare Voyager speed vs Quito speed and assuming angle of Voyager vs Quito is 90 degrees then that should be +- 1.5 kkm/h?
And Earth itself is also according to Google running around the sun at a clip of about 107 kkm/h so that would mean that at some points Voyager is doing -40 kkm/h vs Earth.

Just standing “still” in the Universe some shit would be moving really really fast compared to me so where do we flip reference points?

edit: lost a couple of ks

In: Planetary Science

7 Answers

Anonymous 0 Comments

It’s compared against the sun. The sun is considered the centre for all things in the solar system. It helps because everything nearby like the voyager probe *is* centred around the sun.

And yes the sun is moving relative to our galactic nucleus in a direction. But that can be considered our 0, because our entire solar system is moving at a close speed in the same direction. And so was the voyager before it took off in the rockets.

So it’s like we are all inside a train. If a ball rolls on the floor of the train, it’s easier to talk about the speed of the ball relative to the train, than talk about the speed relative to a lamp far away.

Generally speaking, we would never flip references because it would just cause confusion.

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