Hello again. Last time out, we looked at 10 factors conducive to life, and in doing so, found out why Earth is so special. We also discovered how unique our own solar system is when compared to the others discovered so far.
This time, we’ll extend that exclusivity by taking a peek at the mystery surrounding a possible new member of our solar family.
2.When was it discovered?
In April this year by the Pan-STARRS 1 asteroid survey telescope in Hawaii.
3.Why are we only just hearing about it now?
Because scientists were waiting to confirm their findings. Now they have, they know 2016 HO3 is a stable quasi-satellite of Earth
4.What is quasi-satellite?
A quasi-satellite is an object in a specific type of co-orbital configuration (where two or more astronomical objects – such as asteroids, moons, or planets – orbit at the same, or very similar, distance from their primary) and where the object stays close to that parent body over many orbital periods.
Of interest is the fact that a quasi-satellite’s orbit around the Sun takes exactly the same time as that of the planet it might be bonded to. When viewed from the perspective of the planet, the quasi-satellite will appear to travel in an oblong retrograde loop around the planet itself. In contrast to true satellites, a quasi-satellite’s orbit lies outside the planet’s Hill Sphere (the region where the attraction of satellites dominates). Due to this factor, the orbit of a quasi-satellite is not as stable as a true satellite. Over time they tend to evolve to other types of resonant motion, where they no longer remain in the planet’s neighborhood, then possibly later move back to a quasi-satellite orbit, etc.
5. So, how long will 2016HO3 be with us?
By current estimates? Almost a hundred years. Even then, it will continue to follow a similar pattern as Earth’s companion for centuries to come
6.How big is our new moon?
The actual size of 2016 HO3 hasn’t yet been determined, but NASA’s Jet Propulsion Laboratory at Pasadena, California, says it’s somewhere between 120 and 300 feet in diameter.
7. So we can’t land there then?
Well, we could, but it’s doubtful there’ll be much to see
8. Will it be safe having 2016HO3 so close to us?
Very safe. Unlike approaching objects you see in films like “Armageddon” and “Deep Impact,” this new satellite will keep a distance of at least 9 million miles from Earth and doesn’t pose any threat to human existence
9. What kind of orbit can we expect?
2016HO3 will loop around Earth and drift a little ahead or behind from year to year. You might think that will cause our new moon to drift away? Aha, when it does, Earth’s gravity is just strong enough to reverse the drift and hold onto the asteroid so that it never wanders farther away than about 100 times the distance of the Moon. The same effect will also prevent the asteroid from approaching much closer than about 38 times the distance of the Moon.
In effect, this small asteroid is caught in a little leapfrog dance with Earth.
10.Are there any more moons yet to be discovered?
Most likely…no. As we mentioned, 2016 HO3 isn’t a true moon in the strictest sense of the word, but its stable orbit means it will be a satellite for centuries to come. However, there are other objects out there that have been looked at from time to time: Near Earth Object – NEO – 3753 Cruithne, and Earth Trojan 2010 TK7 were considered, but were later determined to orbit the Sun (not Earth), and appear to lead or follow Earth along the same orbital path.
Of interest is the fact that other small natural objects in orbit around the Sun may enter Earth orbit for a short amount of time, becoming temporary natural satellites. To date, the only confirmed example has been 2006 RH120 in Earth orbit during 2006 and 2007.
So there you go. Another amazing dip into the incredible diversity of our own Solar System
Next time, we’ll take another look at something a little further from home. Mars…as things seem to be developing there quite nicely.
See you then.