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
It’s all relative, and Voyager’s speed of 61.5k km/h is meaningless without saying what it is measured relative to.
Because Voyager 1 and 2 are on a trajectory out of our solar system, it is usually given as speed from the point of view of our sun. This is also what [Wikipedia says](https://en.wikipedia.org/wiki/New_Horizons#Speed) (although not on the page about Voyager 1):
>*Voyager 1*, traveling at 16.985 km/s (61,146 km/h; 37,994 mph) relative to the Sun
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