We may have found the hypothetical Planet 9! Before the 20th century, we had a pretty
good theory that explained a bunch of stuff. It explained the motion of the planets
around the Sun (specifically, it explained why planets follow an elliptical path).
This was the Newton theory. Among other things, it showed that humans can fly on aeroplanes.
It also suggested the idea that an apple and a feather fall with the same acceleration of
9.81 meters per second squared in the void. But then, one day, this theory
was found to be slightly wrong. This is because Einstein gave us a better one,
which included an extended Newton's theory. Einstein's gift was amazing.
Its theory, the theory of general relativity, is the best theory of gravitation we have so far. It fits data, it predicts complex behaviours of
celestial objects, and also it is very precise. For example, when astronomers found that
Mercury's orbit was preceding – shortly meaning that their measurements of Mercury's
orbit period were incompatible with Newton's law- the only possible explanation to that was to add a
perturbation. They thought there should have been something, maybe a planet, perturbing Mercury's
orbit employing its gravitational effect. Astronomers from all over the world were looking
for this new possible planet in the Solar System, and they were calling it “Planet 9”.
But no evidence for Planet nine was found. Instead, it is found that using General
relativity instead of Newton's theory, the mismatched period of
Mercury is soon recovered. They couldn't find any planet nine simply
because...there was no planet nine! As of today, in order to have precise data, we
always take into account General Relativity. And yet something is still unexplained.
For example, the orbits of some trans-Neptunian objects are found to be really weird.
Why is that? Scientists think there could be some possible explanation for that, and some of them
have brought to light Planet 9's existence again. Does planet nine actually exist? Follow me
in this video to get to know more about it! We may have found the first-ever potential
candidate for the existence of planet nine, but we are not so sure about it.
It is located of course somewhere in the Solar System, and if it existed,
we would have a new member in the family. The scientist who claims he may found
planet nine is Michael Rowan Robinson, and he is a really smart astronomer because he
decided to take his data from the IRAS survey. It stands for Infrared Astronomical Satellite
(IRAS), and it was a joint project of the US, UK and the Netherlands. The IRAS mission performed
an unbiased, sensitive all-sky survey at 12, 25, 60 and 100 µm, that is, the infrared
domain (or in simpler words, the red part of the electromagnetic spectrum).
Although the survey is a very old one, it is still so precious for astronomers
from all over the world, since it is a source of very important data about distant
objects such as galaxies and distant stars. IRAS increased the number of catalogued
astronomical sources by about 70%, detecting about 350,000 infrared sources. IRAS
discoveries also included a disk of dust grains around the star Vega, six new comets, and very
strong infrared emission from interacting galaxies as well as wisps of warm dust called infrared
cirrus which could be found in almost every direction of space. IRAS also revealed for the
first time the core of our galaxy, the Milky Way. Among the confirmed results, the
discovery of a ring of cosmic dust that surrounds the Solar System at a
distance of about 15 billion kilometres. Subsequent observation of the sky made
it possible to search for moving objects. Jack Meadows and colleagues have
thus discovered three asteroids, comets and in particular a large dust
tail associated with Comet Tempel-2. Now. Why did Robinson choose to look for
evidence of planet nine in the IRAS data? The answer is: because he is a smart
guy. But let me explain to you better. A few years ago, several scientists started to discover the distant objects that we often
refer to as Trans Neptunian objects, TNOS. Maybe you've already heard of them. Eris,
Haumea Sedna are just three of them. The interesting thing is that a few of them
seem to have possessed very unusual orbits, with specific inclinations and peculiar
behaviours. It is like something is pulling at them, exerting a force on them from
a distant region in the solar system. That's why scientists started to think again
about the possibility of a ninth hidden planet, a hidden object that is not that big, and
it is probably located at a long distance, such that it creates visible effects
on this transneptunian objects orbits. However, this hypothesis was still not a good
one since only a few of them were showing strange behaviours. But in the last six or seven years, a
lot more of these TNOS have been discovered, and some of their orbits did not actually truly
match anything of what we were expecting. Some alternative explanations
for the existence of planet nine have been proposed, and we also talked about them
in a previous video, You can check it out here! https://www.youtube.com/watch?v=9aMWsr1oOM0&t=62s Shortly, some scientists thought that maybe we are
just biased when we're looking for these objects and where exactly we're finding them. In other
words, the existence of planet nine started to be kind of questioned and the scientific community
was still quite divided about its existence. But then, this smart guy came.
He was born in 1942, and he is an astronomer, astrophysicist
and Professor of Astrophysics at Imperial College London. He previously served as head
of the astrophysics group until May 2007 and from 1981 to 1982, and
as Gresham Professor of Astronomy. Rowan-Robinson was awarded the 2008 Hoyle
Medal by the Institute of Physics for his research in infrared and submillimetre astronomy,
and observational cosmology. He conducted an analysis of data collected by
the Infrared astronomical satellite in 1983. What he found seems to be a trio of point
sources that just might be Planet Nine. He concludes his preprint paper, saying that
that is actually fairly unlikely to be a real detection, but the possibility does mean that it
could be used to model where the planet might be now in order to conduct a more targeted search, in
the quest to confirm or rule out its existence. One of the main issues of the study is
that IRAS data are somewhat...obsolete. IRAS used the very first infrared technologies
and so the observations are poor quality ones, compared to the ones we can access
today. In his paper, we can read: "Given the poor quality of the IRAS detections,
at the very limit of the survey, and in a very difficult part of the sky for far-infrared
detections, the probability of the candidate being real is not overwhelming. However, given
the great interest of the Planet 9 hypothesis, it would be worthwhile to check whether
an object with the proposed parameters and in the region of sky proposed, is
inconsistent with the planetary ephemerides." But now the question is: we have
a lot of recent surveys which scanned the night sky. Why did he
choose an old and poor quality one? "Before finding out the answer to this question,
be sure to like or dislike the video so that we can continue to improve and make these videos
better for you the viewer. Plus, be sure to subscribe to the channel by clicking the bell so
that you don't miss ANY of our weekly videos." Well, he choose to go through IRAS data because
it was one of the most important data sources of the last decades.
First of all, it was the first space
telescope to perform a survey of the entire night sky at infrared wavelengths.
But it also discovered some infrared objects that at first made no sense to anyone.
For example, during its operations, it detected several sources of infrared
radiation coming from several stars, but when the scientists used the Hubble space
telescope or a lot of more powerful telescopes, to see if they could have the same results
from those stars, they found nothing. So initially this was thought to be an IRAS
mistake. Maybe something was going wrong with the telescope. But it turned out that IRAS
was actually detecting infrared radiation coming from protoplanetary disks
forming around stars such as Vega. This was not discovered until 2014, using powerful
telescopes (for example Spitzer telescope). So IRAS was about thirty years ahead,
despite its obsolete technologies. Making some calculations and building up some
amazing sets of algorithms, Rowan-Robinson went through all the IRAS data in order to
find the perfect candidate for planet nine, I bet it was a very hard job, but in the
end, he concluded that we may have one. Of the around 250,000 point sources detected
by the satellite, just three are of interest as a candidate for Planet Nine. In June, July, and
September of 1983, the satellite picked out what appears to be an object moving across the sky.
It's not a dead cert, by a long shot. The region of sky in which the source appears
is at low galactic latitude (that is, close to the plane of the galaxy), and
strongly affected by galactic cirrus, filamentary clouds that glow in far-infrared.
So the sources may be noise from these clouds. if we interpret the candidate as real, we can
extrapolate some information about Planet Nine. According to the IRAS data, it would be
between three and five times the mass of Earth, at an orbital distance of
around 225 astronomical units. Dynamical studies are needed to check
whether such an object is consistent with the ephemerides of other Solar System
objects and whether this object can account for the clustering of the orbits of Kuiper
belt dwarf planets," Rowan-Robinson writes. Although its existence has not been proven
yet, direct detection of a ninth planet would be the first discovery of a new planet
orbiting the Solar System in two centuries. But so far, its detection
has proven a little tricky. After the release of the recent paper, Caltech astronomer Mike Brown, who was behind
the 2015 Planet Nine model, took to Twitter to suggest that this may be a different planet
than the one they had initially proposed. So what's next?
As Rowan-Robinson himself proposed, we need to follow up studies! This is a preliminary discovery, maybe
an amazing one, but very preliminary. For example, we need to scan that part of
the sky with the new powerful telescopes. We also may need some other evidence for planet
nine coming from different studies and authors. New evidence would be very useful in order
to confirm the planet existence or not. "This video ends here! Thanks for watching
everyone! What are your thoughts about planet 9? Do you think we will ever find it? Is there
anything more you want to hear? Let us know in the comments below, be sure to subscribe,
and I'll see you next time on the channel!"
