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Today we are going to be taking a look at something that is not quite a moon of the Earth. Before that however, speaking of the Moon, we are on the 14th of July, the New Moon is almost right in front of the Sun, as the New Moon should be. Of course, you wouldn’t really be able to see this with the naked eye, never look directly at the Sun, but the New Moon is there. It is the New Moon, it’s more or less directly in front of the Sun. Of course it’s not directly in front of the Sun, it’s not causing an eclipse. However, the next New Moon after this one on the 12th of August will cause a solar eclipse. The eclipse coming up on the 12th of August, we are just entering the lunar cycle that will lead up to that eclipse on the next New Moon, but we’re not looking at the Moon for this video. Instead we’re going to look for something that’s called a quasi satellite.

A quasi satellite is something that is interacting with the Earth’s gravity, it’s usually orbiting the Sun at the same distance as the Earth and being at least influenced by our gravity, but not actually orbiting us. You may remember from a previous piece, the asteroid Cruithne, named after a Celtic tribe, that is a quasi satellite of the Earth, but we are going to be looking for a different quasi satellite today, Kamo’oalewa. Kamo’oalewa is an asteroid. It’s not up at night-time at the moment, and it’s only magnitude 24 and a half, so it’s definitely quite a faint object. We’ll bring it above the horizon and we will get rid of the atmosphere just so we have a better idea of where it is. If we take a closer look, we’re not going to see very much. This is an asteroid that was discovered fairly recently, 2016 is when this asteroid was discovered. It is fairly new to science, but the way that it moves around the Earth, as it turns out, it’s been there for centuries and will likely stay there for centuries to come. So this is a stable quasi-satellite.

It’s not orbiting us directly in the same way that the Moon is, this little asteroid is moving in such a way is that it does seem to go around the Earth, but really it’s orbiting the Sun and moving around the Earth almost incidentally, just because it happens to be going around the Sun in nearly the same place as the Earth. Taking a look at the distances, it’s just about 1 AU from the Sun and it’s almost 0.2 AU from the Earth, so it’s fairly close to us. We’ll get rid of the ground just so we can follow it without worrying about it going under the horizon or getting blocked out. We can see that it gets a little further from us up to about, to 0.3 AU and it gets down to just about 0.1 AU from us. It’s staying fairly close to the Earth, it’s distance from the Earth never goes that high, it’s just getting up to 0.3 AU and then it drops back down, so it never gets particularly far from the Earth. It never gets too close either, even 0.1 AU, is 15 million kilometers and 15 million kilometers is still pretty far away.

It does go between us and the Sun, its distance to the Sun goes down to under an AU, just 0.899 AU away from the Sun. It is 0.128 AU from the Earth, and it is almost 0.128 AU closer to the Sun than we are, its distance from us is almost the distance it is closer to the Sun. Then again, the Earth’s distance to the Sun isn’t always exactly 1 AU. Either way, this is pretty much when it’s directly between us and the Sun. We’ll keep moving forward, we’ll get back to the opposite condition. We’ll get up to its furthest distance from the Sun, which is just 1.105 AU by the looks of it. That’s 165 million kilometers from the Sun and it’s 0.205 AU away from us. It’s not exactly 0.205 further from the Sun than we are, which should mean that it’s not exactly at opposition when it’s at its furthest from the Sun. Then again, as I mentioned the actual distance of the Earth varies. It’s still around magnitude 24, but let’s see if we can get it into opposition and get that magnitude down to something a little bit lower. It doesn’t seem to go particularly low and of course with magnitude low numbers means brighter. It gets down to 22nd magnitude, which is way too faint for us to see with the naked eye. We’ve moved through a couple of years now, and it is staying with us as we move around the Sun. It never gets too far away from us.

We’re going to head out to the solar system observer and we’re going to take a look at the behavior of this object, how it orbits, from above. Now, hopefully, we will be able to see it fairly close to the Earth but following objects from the perspective of the solar system observer is a little bit tricky. One important thing that we’re seeing is that the elements are for epoch 2016. The orbital elements, the orbital calculations, from 2016 are being used, which is probably outdated, and that’s because this was discovered in 2016 so that’s presumably where the original calculations come from. They have been updated, but they haven’t been updated in Stellarium. We’re going to bring up the orbits of objects in the solar system, but it is a little bit crowded. With the orbits turned on for the selected object, we’re not getting an orbit for this asteroid. If I turn on the orbits for everything, there are a lot of orbits out there, but it’s still not showing the orbit for this asteroid. Regardless, we’re going to move through time, it is close enough to the Earth that we can see the Earth as we move through time. So we can see that this object kind of looks like it’s orbiting the Earth, it’s trailing behind the Earth, catching up to the Earth, moving ahead of the Earth, and then falling behind the Earth.

It does almost look like an orbit, but what’s really happening here is that this asteroid is orbiting the Sun, and it happens to be so close to the Earth that the Earth’s gravity can influence it without holding it. We need to follow it from one end of the cycle to the other, so we’ll start with the object trailing the Earth. With the asteroid behind the Earth, it is initially further from the Sun than the Earth, but as we move forward, it ends up closer to the Sun than the Earth. With the asteroid closer to the Sun than the Earth, that means it’s going to orbit the Sun faster, the same way Venus and Mercury orbit the Sun faster than the Earth. That means the asteroid is now orbiting the Sun faster than the Earth. As it comes past the Earth, there’s a little bit of an energy exchange, the Earth’s gravity affects this asteroid, the asteroid is moved and influenced by the Earth. At first it continues to pull ahead, but it slow down and moves to an outer orbit, it is now further from the Sun than the Earth is. Of course it’s now going to orbit the Sun slower, just like Mars. That causes it to fall back while it’s further from the Sun than the Earth. It’s still getting a little influence from the Earth’s gravity, there’s still a little bit of a tug going on, but more importantly, as it drops behind us it falls back down to a lower orbit closer to the Sun. This lets it speed up and it speeds past the Earth again.

So this is a quasi satellite. It is near the Earth, it’s been near the Earth for centuries and it’s going to keep doing this thing where it passes by the Earth to and fro for centuries to come, but it is only a quasi satellite. It could easily get disturbed, something could happen that throws it out of position. It is currently around the Earth and has been for a while and will do for a while, but it’s not quite the same as our Moon. Speaking again of our Moon, we’ll come back to the Earth and we’ll keep pushing back to closer to the current date, back into 2026. We’ll get the atmosphere and the ground turned off again so that we can keep an eye on this object. As I mentioned, when we take a closer look at this object, we’re not really seeing anything, and that’s because it is a very small asteroid. It is just a little fragment and that’s pretty much what the name of the asteroid means. “Ka mo’o” is a fragment or a piece and “a lewa” is “that is oscillating” or moving around, that is moving where it is. This is from Hawai’ian, where “lewa” or “lewalewa” means oscillating, to kind of move back and forth. This does oscillate, it oscillates around the Earth. So that is a fairly accurate way to describe describe it. It is a fragment that oscillates,

There is a chance it’s just called a fragment because it’s a little bit of rock and it’s a coincidence that it has been theorized that it’s an ejection fragment of the Moon. I don’t think it’s a coincidence. Currently, we think it’s an ejection fragment of the Moon, but we don’t know for sure yet. However, there is a spacecraft, Tianwen-2, on its way to this asteroid. We now have better images of this asteroid thanks to the spacecraft that is now quite near to it, and hopefully we will find out soon if this asteroid is actually a piece of the moon that broke off, and maybe that’s why it is so close to the Earth. Maybe that’s how it entered into this quasi satellite orbit, because it came off of something that’s already in orbit around the Earth. That’s not always the way with quasi satellites.

I do have a past video on Cruithne, another quasi satellite of the Earth, but Kamo’oalewa is one quasi satellite of the Earth that is in the news recently because there is a spacecraft very near it and we’re getting to know more about this object. I hope you enjoyed getting to know more about it here. If you did, then please do like this piece. If you enjoy this kind of content, then please subscribe to this website and my YouTube channel. Thank you very much for reading and hopefully I’ll see you back here next time.