Thousands of worlds may lurk beyond Pluto — and a stunning new animation shows the ones we’ve found – Business Insider


solar system space map orbits nasaNASA

  • A new animation shows the orbits of hundreds of dwarf
    planets beyond Pluto.
  • The astronomer who compiled the data says it may
    capture only a small fraction of dwarf planets in the solar
    system.
  • A new definition of “planet” may categorize many dwarf
    planets and moons as planets.

You may be familiar with our solar system’s eight planets —
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and
Neptune. There’s also their famous dwarf-planet companion,
Pluto.

But this icy world may just be an appetizer to what lurks in a
region beyond Pluto called the Kuiper Belt.

As this stunning animation suggests, dwarf planets may outnumber
regular planets hundredfold or even thousandfold:

However, if a small group of astronomers gets its way, many of
these objects will become full-fledged planets and drop the
“dwarf” label.

Where the animation comes from

We first saw the animation in
a Reddit post
by user Nobilitie. It’s actually a recording of
a physics-based simulator game called “Universe Sandbox 2,”
according to Dan Dixon, the
creator and director of the software.

Each ring represents an object’s orbit, and the mess of rings
beyond the inner eight rings belong to dwarf planets.

In response to the Reddit post, Dixon said the orbits were based
on a constantly updated
list
of candidate objects. The list is maintained by Mike Brown, an
astronomer at the California Institute of Technology.

“It’s a nice illustration of what is out there,” Brown wrote in
an email to Business Insider. “The striking difference between
the orderly giant planets and the randomness of the dwarf planets
is quite apparent.”


Eris
An
artist’s impression of the dwarf planet Eris.


ESO/L.
Calçada and Nick Risinger
(skysurvey.org)



Brown discovered Eris, a 10th solar system object that’s about
27% more massive than Pluto. His find eventually “killed
Pluto as a bona fide planet — in 2006, thousands of astronomers
voted on
new celestial terminology
, categorizing Pluto as a dwarf
planet
alongside Eris.

Some astronomers disagreed with the decision (one
called it “bulls—“
). The public also didn’t take it well —
Brown said he has since received a torrent of hate mail from
schoolchildren.

Definitions aside, the list kept by Brown sorts objects detected
in deep space based on the likelihood of their existence. Larger,
inner objects tend to be more certain, while farther objects are
less certain.

Pluto, Eris,
Ceres
, Makemake, Haumea, and five others meet Brown’s “near
certainty” criteria — in other words, they’re definitely dwarf
planets and not comets or other astronomical objects. Thirty are
“highly likely” to be dwarf planets, 75 are “likely,” and nearly
850 are “probably” or “possibly” dwarf planets.

Brown guessed that about half of the dwarf-planet candidates have
yet to be detected, bringing their numbers close to 2,000 or
more.

Redefining ‘planet’?


pluto orbit solar system kuiper belt objects map nasa jpl
An
illustration of Pluto’s orbit is shown in yellow. The dots beyond
it are Kuiper Belt objects.


NASA


Even Brown’s best estimate may be low, though.

“As you can see from the illustration, some of them are on
exceedingly elliptical orbits. Those guys are going to spend most
of their time at the outer edge of their orbit, so they’re hard
to see,” Brown said. “There might be a factor of ~5 more of those
objects that we don’t know about.”

But Brown says he doesn’t think
nuclear-powered spacecraft
like New Horizons — which is

now exploring
the Kuiper Belt — will discover most of those
missing worlds.

“The fact that there are so many of these things out there really
shows that the future of their exploration is going to mostly
rely on telescopes,” he said.

A twist in all this is that astronomers are once again wondering
what to call floating orbs of rock, metal, and ice in space,
according to a
poster
that seven researchers are presenting this week at the

48th Lunar & Planetary Science Conference
.

Instead of categorizing objects as planets, dwarf planets, and
moons — terms based on their orbits of the sun and one another —
the team wants to simplify the system: If an object is big enough
to be mostly round and isn’t fusing hot gases (like the sun), it
should be deemed a planet.

If enough astronomers agree with them, in time the solar system
may be said to
contain 110 official planets
— and perhaps hundreds or even
thousands more if Brown’s list of candidates pans out.

Thousands of worlds may lurk beyond Pluto — and a stunning new animation shows the ones we’ve found – Business Insider

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