A picture from back in 2010 that shows us the first ever confirmed trojan of planet earth now I’m going to explain to you what trojans are in a few seconds but what's important is that it looks like we found another one there seem to be two trojans that planet earth has and that is actually kind of fascinating but like so many other amazing discoveries and amazing stories this one actually once again starts on twitter the amazing amateur astronomer Tony Dunn has actually posted this beautiful picture you see right here that shows us the potential orbit of this incredible new discovery now first of all what exactly are trojans and why is this even important like so many other unusual objects in the solar system trojans are a type of an asteroid although more specifically they're known as minor planets and if I were to select some of them right here you would see there's actually quite a lot of them placed in the orbit of Jupiter or essentially sharing the orbit with Jupiter.
If you ever want to see the total list
of these over 9 000 objects it's actually in the description below there are
quite a lot of them and they all have very different properties but those are
only the Jupiter’s trojans we've discovered so far in reality there are
millions and millions of them and a lot of them are still hidden and every
planet has their own trojans the objects that essentially share the orbit of
the planet by getting stuck in these relatively stable points known as LaGrange
points you may have heard of them before you may have not there are five of
them in total they're all relatively stable and you can actually take any
object places it there and it's not going to fall back to earth and it's not going
to fall back into the sun there's one point right here between the sun and
planet earth there's one behind planet earth there's one on the opposite side
to the sun and there's also l4 as well as l5 which are roughly around 60
degrees between the planet earth and the point itself and all of the trojans we
found so far are basically in these l4 and l5 points and by the way we also use
them for different satellites as well it's very common to place a satellite that
for example tries to study planet earth or something away from planet earth by
placing it in these points but because of the proximity of Saturn to Jupiter.
Essentially because of the
planetary interactions and because Jupiter is really massive so far, we
actually haven't discovered any trojans around Saturn we've discovered one around
Uranus there's I think 28 around Neptune but Saturn seems to be lacking them and
it's not really because they're just not there they're probably there or might
actually be really small but no major ones have been found and we believe this
is really because of the gravitational interactions with Jupiter meaning that Jupiter
probably just stole all of them and now they are orbiting the other planet but
surprisingly mars have nine of them.
That means that earth has to have
some too earth is more massive it also has quite a lot of asteroids approaching
it once in a while so there have to be more trojans hiding somewhere in there this
is what most scientists believe and this is what a lot of professional and amateur
astronomers have been trying to discover for years now but the only official confirmation
was back in 2010 and since then nothing new has been found until of course now and
unfortunately, other than the potential orbit that you see right here we don't
really know much else about this object we know that it's obviously a
relatively large asteroid probably somewhat similar to the previously discovered
trojan which is around uh 300 meters in diameter or approximately thousand feet
and just like the previous discovery it also has an orbit that essentially is a
little bit more complex than just staying in that one spot and so instead of
just being in the LaGrange point it actually moves in a really wide arc even
going as far as the orbit of Venus although wait it's on the other side it's in
the l4 point which is the point preceding the orbit of earth and as you can see
in this simulation it even almost reaches the orbit of mars and in that sense
it's actually a really interesting object because first of all this means that eventually
either Venus or mars will destabilize this orbit and so the object will
probably move away possibly escaping somewhere else or even becoming a trojan
of either mars or Venus.
But at the same time now I guess
the question would be how can it stably orbit there to begin with shouldn't Venus
already have disrupted it and well remember this is a two-dimensional image in
reality this object also has a really high inclination meaning that it goes below
and above the solar system plane thus, never really coming too close to Venus
or mars and this is also one of the main reasons why it's somewhat difficult to
find these objects they move across the night skies quite a lot and quite
unpredictably while at the same time they're usually in the location where the
sun has a tendency to cover their presence so, it's very difficult to find
these objects from planet earth and one of the best ways for us to try to find
more of them would be to actually look at the orbit of planet earth from
another planet although obviously that's not something we can currently do just
yet and several other astronomers have already joined in and tried to simulate the
stability of this object.
And it turns out it's going to be
in this relatively stable orbit for at least a few thousand years and this is
of course as stable as it gets for most of the trojans or between smaller
planets only trojans of Jupiter for example or possibly Neptune would be able
to stay in these orbits for much longer periods of time so for example the
first ever discovered trojan is expected to stay in this orbit for probably
about maximum 18 000 years before it gets captured by something else or
possibly collides with something and one of the main reasons why these objects
normally do not have stable orbits for over a few thousand years is actually because
of the pressure from the sun not so much the pressure from Jupiter's gravity in
this case we're talking about something known as the Tarkovsky effect the
effect that starts appearing in any asteroid or any smaller object that spins
around while orbiting the sun that basically is explained by one side of the object
being warmed up and as it spins around that one side that's now warm emitting
the radiation that can actually act as a tiny engine kind of like a rocket engine
pushing the object away toward a certain direction and this is a pretty
powerful effect especially for some of the medium-sized asteroids to the point
where sometimes we don't even know where a certain asteroid is going to be in
the next few hundreds of years.
There's actually a little bit more information
about how this can be important for us and how it can actually lead to
potentially dangerous collisions in one of the videos I made about the famous Apophis
asteroid the video is somewhere right there but for the object officially known
as 2020xl5 without an actual proper name. At least 4 500 years so definitely something
that hypothetically at least we could one day explore although because these
objects have such high inclination or basically because their orbit is highly
inclined to the rest of the solar system it's somewhat difficult to get to them.
To try to reach this you would probably need just as much fuel as to reach Jupiter
so in that sense even though they do share the orbit with planet earth because
of their inclination it is kind of difficult to get there but in reality, once
we find out how to find these objects more effectively we could actually
discover up to about a hundreds of them that's sort of the unofficial figure
right now for how many we believe there should be out there or between these l4
l5 lag range points and before we forget speaking of trojans.
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