Are Satellites in the sky or are they in space?
In: Planetary Science
Satellites are things that orbit something. The moon is a satellite of earth, the earth is a satellite of the sun. Colloquially, space is everything beyond our atmosphere and the sky is everything you can see from the ground looking up.
TL,DR The metallic communications satellites are called satellites because they orbit the earth, same as the moon.
things in space are in the sky, things in the sky are not necessarily in space. There is no clear line between where space begins, but most people would consider things that are in orbit to be in space.
“Space” is generally accepted to begin 100 km above sea level, but this is an arbitrary boundary. There is no hard edge between the atmosphere and outer space.
However, stable orbit is not generally possible anywhere near that altitude because of atmospheric drag. A Japanese program creatively called the “Super Low Altitude Test Satellite” (SLATS) was launched in 2017 to test a so-called “very low Earth orbit” (VLEO). It was able to orbit at 167.4 km for a week, which was recognized by Guinness as the world record lowest altitude satellite. It was decommissioned in 2019.
In contrast, the ISS orbits around 420 km, which is considered “low Earth orbit” (LEO). Most communications satellites are in geostationary orbit, which is about 36,000 km.
There are “low orbit satellites” that lays between earth’s denser part of the atmosphere (atmosphere doesnt have a clear dividing wall, it just “fades” to space.) and the VanAllen radiation belt. They could be considered “in the sky” as they arent quite in “outter space” but its at a height no human without protection can get to.
High orbit satellites are definitely in space.
Generally speaking, “space” begins at roughly 150km above the earth. But satellites orbiting the planet, even in low earth orbit (LEO), circle the planet no lower than 160km but most are higher. The ISS orbits at 400km. So, “sky” can be assumed to be under 150km.
Tibetans use the same word, namkha, for both sky and space. There’s just as much space in your furniture as there is past Jupiter
I don’t think the ‘sky’ is a place. Rather, it is the image we see when we look up above anything attached to the ground.
So I’d say the stars (which are much further away than any satellites), and in the sky, as are the sun and moon, because they are part of that image we can see.
i.e. I’d say that satellies are in space, and are visible in the sky.
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Wikipedia claims that “The Kármán line, an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping.”
A google search suggests that many sattelites are in the 1000’s of km range, so well above that line. Britannica says “Satellites do not orbit below 160 km because they are affected by atmospheric drag.”
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