
 “Farout”, the Farthest Object Ever Seen in the Solar System - mpweiher
https://www.universetoday.com/140901/just-discovered-farout-the-farthest-object-ever-seen-in-the-solar-system/
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sctb
Previous discussion:
[https://news.ycombinator.com/item?id=18700144](https://news.ycombinator.com/item?id=18700144).

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retSava
I think the most interesting part is at the end of the article: "Their work
indicates the potential presence of an enormous planet, perhaps up to 10 times
the size of Earth."

Dwarf planets are apparently somewhat plentiful in our solar system, but such
a giant would really tickle the fantasy even if far from the sun.

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dsfyu404ed
I suspect that in the next ~30yr we'll either find planet 9 or find something
else to explain the odd orbits of small things beyond Neptune. There's been a
ton of progress in our understanding of that part of the solar system in the
last 20yr.

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walrus01
Looking at the Wikipedia page there are a number of trans neptunian objects
with much greater aphelions:

[https://en.wikipedia.org/wiki/2018_VG18](https://en.wikipedia.org/wiki/2018_VG18)

It is just the farthest out _right now_.

[https://en.wikipedia.org/wiki/Extreme_trans-
Neptunian_object](https://en.wikipedia.org/wiki/Extreme_trans-
Neptunian_object)

There are likely many, many more we haven't found yet.

[https://en.wikipedia.org/wiki/Sednoid](https://en.wikipedia.org/wiki/Sednoid)

For comparison it is often announced in the media that voyagers 1 and 2 have
"left the solar system". Voyager 1 is about 144AU out right now. There are
things in orbit of the sun with aphelions from 1500 to 3000AU.

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josephhainline
The same folks also discovered
[https://en.wikipedia.org/wiki/2015_TG387](https://en.wikipedia.org/wiki/2015_TG387)
a while back, with a 1955 AU aphelion. That is a lot more far out. It's crazy
to think about an orbit taking over 32 thousand years. I wonder what the sun
looks like from out there.

~~~
walrus01
Yeah, I remember that. There is speculation in the astronomy community that
based on the sheer amount of cubic volume that is out there, the distance, the
small size and dark color of Sednoids and other TNOs, and the small area
that's been systematically searched so far, that there may be literally
thousands of them out there and a total mass of 75% of Jupiter.

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8bitsrule
It may be 'far out' now, but in ~ 500 years it comes in as close as Saturn!
(And the orbit's inclined 31 degrees.)

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spuz
What? The article says they do not know the orbit so why do you say that?

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KnightOfWords
The orbit isn't well known, too short an observation arc, but a rough one has
been calculated. It probably reaches somewhere between Uranus and Neptune, but
not Saturn.

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karthickshiva
Vadai!!!!!

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tjpnz
How long will it be before they discover "Even Farther Out"?

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okket
That has to wait until the Ludicrous Large Telescope has been built.

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traverseda
For more on that see: [https://xkcd.com/1294/](https://xkcd.com/1294/)

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lordnacho
The first diagram, of the distances from the sun of those objects including
the classical planets, it's not really a sensible thing to show.

If you look at the second diagram some of the orbits are very elliptical so
the distance from the sun changes significantly. And it's also not the case
that one objects it always the same "rank" from the sun.

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EForEndeavour
The article mentions that the orbital elements of Farout (2018 VG18) are
currently unknown. We don't know if its orbit is similar to the eccentric
orbits of the other minor planets mentioned. All we know is that it is
currently about 120 AU from the sun.

"2018 VG18 is much more distant and slower moving than any other observed
Solar System object, so it will take a few years to fully determine its
orbit."

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Cthulhu_
Why does the article keep referring to it as a planet? That's highly confusing
and disingenious, as in, probably trying to get the pop sci sites to start
yelling about it as a planet.

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toyg
Genuine question from an astronomically-challenged person: why would this
_not_ be a planet?

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shaqbert
The International Astronomical Union defined a planet [0] as an object that:

(a) orbits the sun, (b) has sufficient mass to be round, or nearly round, (c)
is not a satellite (moon) of another object, and (d) has removed debris and
small objects from the area around its orbit

The dwarf "planets" often suffer from not being round (enough), and even more
from not clearing out their debris in their orbit.

[0]: [https://www.space.com/25986-planet-
definition.html](https://www.space.com/25986-planet-definition.html)

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hibbelig
Well, Farout orbits the sun, is round, is not a moon. The article is silent on
item d.

I don't know what to do with the information that its diameter is 500km. I
guess that makes it 1/5 of Pluto's diameter, and given that Pluto is called a
dwarf planet...

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zamadatix
"round" is a bit oversimplified in the above the actual criteria is:

"(b) has sufficient mass for its self-gravity to overcome rigid body forces so
that it assumes a hydrostatic equilibrium (nearly round) shape, "

If Farout is highly icy 500km could be enough to qualify it.

Regardless it isn't nearly massive enough to clear it's orbit.

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Jenz
Can someone explain just What it is? A planet?

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lincolnq
It's about 1/5 the diameter of Pluto (500km to Pluto's 2400), so quite small
and definitely not a planet. It's interesting because it could give evidence
about the hypothetical ninth true planet-sized object that people have been
hypothesizing for awhile.

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Jenz
Thanks! Hoping for that ninth planet :D

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ridgeguy
How could they not have named it Farpoint?

Q is not impressed.

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dcminter
Semi-off topic, I suspect someone's a Pratchett fan:

 _' Correct. The Bank is now in orbit forty million miles out beyond - what's
the name of your outermost world?'_

 _' Far Out,' said Tarli._

\-- 'The Dark Side of the Sun', Terry Pratchett

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qwerty456127
Its Yuggot!

