Context I was watching a video about the JWST and saw that it orbited the sun at the L2 point, but that got me wondering as to how it doesn’t slowly drift in its orbit, considering its at a higher (but presumably at a similar eccentricity to that of the earths) orbit. Are higher orbits not always slower?
Basically how does the JWST not fall behind the earth, for lack of better phrasing.
In: 6
Lets assume that the orbits I’m discussing are all more or less circular, and define a ‘slower’ orbit as one where it takes more time to complete an orbit. If you’re considering just a small object orbiting a big object then higher orbits will be slower.
However, if you have a small object orbiting a big object, and somehow make the big object even bigger then the small objects orbit will be faster than it was before the weight gain.
The way the ‘L2’ point works is that the Sun and Earth both pull on the object in the same direction, this is basically the equivalent to the ‘bigger object’ idea above. So if you compare an object orbiting at L2, and one that is just orbiting the Sun at the same distance, the L2 object is faster because it’s getting ‘extra’ pull from the earth. The L2 point being the spot where the ‘fastness’ from the extra pull exactly cancels out the ‘slowness’ of the object being farther from the sun than earth.
ohhh, it’s been a good day for ELI5.
First of all, a stationary L2 is a bit different than an orbital L2. Since you’re just asking about the stationary, it’s pretty simple. That’s just the point where the earth is tugging on it as hard as the sun is tugging on it.
It’s not quite an orbit, more like it’s just the point where it’s falling into the earth at the same speed it wants to fall into the sun. Of course the earth orbits the sun, so it has to follow at the same speed to keep those distances equal.
This isn’t quite as stable as a normal orbit, so it needs to make course corrections every couple of years to keep from falling too close to the earth or sun
It depends on the Lagrange point.
L1 (between the sun and planet) and L2 (on the side of the planet away from the sun) are only quasi stable. Think of it like balancing on the saddle of a horse. It takes occasional thruster firings to cancel out the small perturbations from things like the solar wind and the influence of the moon.
Also, the actual exact point isn’t all that useful. In the case of L1, it would actually be impossible to receive data from a probe at L1, as the radio noise from the sun would drown out the transmission from the probe. In the case of L2, the sun would be blocked by the earth, making solar power untenable.
Instead, the probes are in orbits that appear to orbit around these points. Aside from the practicalities mentioned above, this requires less fuel. This is part of the reason why SOHO has been able to stay functional for 28 years, despite being only planned for a 2 year mission.
L4, and L5 are points leading and trailing the planet, where the gravity equals out. These are inherently stable regions (think sitting at the bottom of a cup) but they’re not much use at the moment.
L3 is at the far side of the sun, and is north useless since we can’t communicate with it due to the sun being in the way, and is very unstable (think balancing on the head of a nail).
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