Astronomers May Have Just Discovered Our Solar System's Sixth Dwarf Planet (scientificamerican.com) 51
Astronomers using the Vera C. Rubin Observatory have discovered 2026 ED138, a large object beyond Neptune that could become the solar system's sixth recognized dwarf planet if further observations confirm it is massive enough to be round. Located about 46 times farther from the Sun than Earth, the object is estimated to be 600 to 1,500 kilometers wide and had remained hidden because it lies against a particularly crowded field of Milky Way stars. Scientific American reports: The discovery was made by running billions of pieces of data collected by the Rubin Observatory through a search code developed by Center for Astrophysics | Harvard & Smithsonian astronomers Matthew Holman and Kevin Napier. "My first reaction was one of excited disbelief," Holman said in a statement. "Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong."
When Holman and his colleague Mario Juric of the University of Washington went to double-check, they found 30 more observations of the object by Rubin that dated to between March and July 2026. Looking at other observation tools, the pair found even more sightings going back to 2016. Together, these data allowed the astronomers to begin mapping out 2026 ED138's orbit. The suspected dwarf planet is about 46 times as far from the sun as Earth, making it even more remote than Pluto, which is just 40 times as far. The object is also tilted off the solar system's plane by around 25 degrees, an arrangement that could be linked to disruptions caused by Neptune's gravitational pull.
Initial measurements indicate that 2026 ED138 has a diameter between 600 and 1,500 kilometers (373 and 932 miles), which makes it one of the largest dwarf planet candidates yet detected. But size isn't all that matters: further observations are required to determine if the object has enough mass to be pulled into a round shape, which is a key requirement for a dwarf planet. Despite its size, 2026 ED138 was able to avoid detection for all these years because it's located in a part of the night sky that's crowded with stars whose light drowned it out.
When Holman and his colleague Mario Juric of the University of Washington went to double-check, they found 30 more observations of the object by Rubin that dated to between March and July 2026. Looking at other observation tools, the pair found even more sightings going back to 2016. Together, these data allowed the astronomers to begin mapping out 2026 ED138's orbit. The suspected dwarf planet is about 46 times as far from the sun as Earth, making it even more remote than Pluto, which is just 40 times as far. The object is also tilted off the solar system's plane by around 25 degrees, an arrangement that could be linked to disruptions caused by Neptune's gravitational pull.
Initial measurements indicate that 2026 ED138 has a diameter between 600 and 1,500 kilometers (373 and 932 miles), which makes it one of the largest dwarf planet candidates yet detected. But size isn't all that matters: further observations are required to determine if the object has enough mass to be pulled into a round shape, which is a key requirement for a dwarf planet. Despite its size, 2026 ED138 was able to avoid detection for all these years because it's located in a part of the night sky that's crowded with stars whose light drowned it out.
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If objects like this were at all interesting we'd be flying around lunar caves in bat suits by now
If Uranus dug deep into the darkest smelliest parts of our galaxy, it still wouldn't find a reason to get excited about dwarf planets after Plutos fuckening.
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Yeah! You can take our Pluto but you can also take your dwarf planets and categorize them next to uranus
Re:moon (Score:5, Interesting)
Speak for yourself, Pluto is fascinating. Tectonically active. Cryovolcanism so abundant it appears to have formed large mountains by the merger of individual domes. A gigantic scar exposing its mantle, which over time roils in massive convection cells, pockmarked in sublimation pits. Mountains drifting like icebergs and accumulating on the shore. Penetentes (sublimation ice spikes), the size of large hills. A multilayer blue atmosphere, in which organic chemistry occurs, depositing not just organic matter onto its own surface, but that of its moon as well. Active glaciation. A probable subsurface ocean, in contact with rock. Conditions suggesting it was habitable when it formed.
IMHO, it's way more interesting than a number of recognized planets.
(Also, I'm confused by your response. This isn't about the moon, and the moon has no atmosphere for flying)
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Warning! (Score:5, Funny)
Objects in Mirror Appear Smaller Than They Are (*)
(*) Astronomical telescope joke.
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Yeah, but...
The guess at the size is based on the guess of the albedo. If it's covered with something dark, it a LOT larger. (I'm presuming they're guessing it's covered with methane ice.)
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The list of people who will find that funny is planetesimally small.
Occultations? (Score:2)
If there were so many stars behind this object, shouldn't we have noticed it blocking stars as it moved?
Re:Occultations? (Score:5, Informative)
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This! A lot of people don't realise just how much black there is between stars and just how small objects are. For those people who have a hobby of measuring occultations it is usually a very carefully calculated trajectory that may draw a path across the earth only a couple of 100km across, often much tighter than those of full solar eclipses.
Noticing this kind of thing by happenstance rarely happens. I say rarely because a freak incident did occur to a friend of mine, but even that incident had a mitigati
Re: Occultations? (Score:5, Interesting)
Up until very recently weâ(TM)ve not really been looking at large areas of the sky repeatedly every night. There were likely thousands of occultations and we just didnâ(TM)t see them because we werenâ(TM)t looking at that particular bit of the sky when they happened.
Vera Rubin came online a few months ago, and has precisely that job - to take images of a large portion of the sky with a very wide angle very high resolution camera, and compare them every few nights. The result⦠oh look - thereâ(TM)s a dwarf planet, not just occulting things, but reflecting light.
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While that's true,
1) We're not talking about an asteroid-sized object
2) We're not talking about one object occulting things
3) We're not talking about one object being occulted.
While you're right, that through pure chance, the likelihood of taking a shot of one particular asteroid occulting one particular star if you take a shot once every 3 nights is near zero. However... one shot from vera rubin captures on average 10,000,000 stars, and around 1000 potential occulters. It's estimated that an occultation
Pluto is a planet (Score:1)
Re:Pluto is a planet (Score:5, Informative)
False. A dwarf planet is not a planet. It's a completely exclusive definition incompatible with the definition of a planet. Both share a parent definition of a celestial body, specifically a planetary-massed celestial body orbiting a star. But that's it.
You looking at words in isolation desperately crying crocodile tears over Pluto has nothing to do with the scientific definition. You can adopt the correct definitions, or you can be incorrect.
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Except I'm right, given that the official definition of a planet and a dwarf planet are mutually exclusive. Here let me help you:
Planet:
c) has cleared the neighbourhood around its orbit.
Dwarf planet:
c) has not cleared the neighbourhood around its orbit, and is not a satellite.
I highlighted the relevant word in bold. You're on Slashdot so I hope I don't need to explain the logical "NOT" operator to you.
my logic is still better than the IAU since not even Earth, Jupiter, or Neptune have completely cleared their orbit.
Remember how I said you're wrong. Try reading up the definition of a planet again. Here allow me to give yo
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Don't be hypnotized by the names. What is most significant (after the orbit) is the mass. And that's a pretty smooth gradation (at least on a logarithmic scale).
If you want "planet" to mean "stuff in orbit around the sun", you end up with most planets weighing micrograms...or possibly less.
N.B.: By the strict definition of "planet" used by the IAU, even Jupiter wouldn't really qualify, because it hasn't cleared it's orbit. There's a lot of small stuff and, of course, the trojans.
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Supporters of the IAU definition (which I should add was a deeply biased sample, in that it looked like they were headed toward no definition or a hydrostatic equilibrium definition, so most supporters of that left, but the people trying to switch it to an orbit-clearing definition stayed) will argue that it's cleared if the remaining objects are trivial transients or in orbital resonance. But that's not what the IAU definition says. Also they'll point to the Stern-Levison parameter, but (A) that was based
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which I should add was a deeply biased sample, in that it looked like they were headed toward no definition or a hydrostatic equilibrium definition, so most supporters of that left, but the people trying to switch it to an orbit-clearing definition stayed
Thank god for that. It was hard enough to learn 9 (now 8) planets at school. Can you imagine having to learn all the names if the hydrostatic equilibrium definition held? The KBOs alone would be a pain to learn.
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Since when does science work by a standard of "what is easy for children to memorize lists of"? Do we say "There are 8 rivers in the world, and all others are dwarf rivers, which really aren't rivers" to make it easier on kids? Do we say "There are 8 bones in the human body, and all others are dwarf bones, which don't really count as bone
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Funny :D
I want to ride in my dwarf boat an a dwarf river collecting dwarf bones from crocodiles, unfortunately they are bigger than my boat :(
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N.B.: By the strict definition of "planet" used by the IAU, even Jupiter wouldn't really qualify
Sure it does. Jupiter is, per IAU definitions, a planet.
because it hasn't cleared it's orbit. There's a lot of small stuff and, of course, the trojans.
That's true. I suggest the issue you're having with definition here is: what is the definition of "cleared it's [sic] orbit"? Here is some info about what the IAU has said about that: https://en.wikipedia.org/wiki/... [wikipedia.org]
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It turns out that the IAU calls the orbit "cleared" even if there is small stuff and trojans about. Much like I can call my bedroom floor "cleared" even though there is dog hair still about. The local Marital Union has declared that this meets the definition. However we have agreed that there may be no trojans on a "clean" floor.
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I actually think that you could craft good arguments for allowing trojans. It's the stuff in temporary resonance orbits that I was really thinking of. There are a lot of orbits that are only semi-stable, say stable for a century or two, but not for millennia.
Re:Pluto is a planet (Score:5, Funny)
Do you know that The Moon of America is three times larger than Pluto?
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Do you know that The Moon of America is...
You mean Trump?
Usually he wears pants.
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I hadn't heard the YOB had offered to rename the moon, but one third is only by volume. For mass it's about one sixth and diameter would be around two thirds... (At least that's what the genAI told me, and I can't imagine why it would hallucinate again.)
But I think the seventh dwarf joke was funnier, even though I can't remember the song he must be referencing. I'm guessing it's a Disney thing?
Me? I suppose I prefer my politicians feckless and "mostly harmless" rather than dictatorial profiteering wolves in
Can't wait until they find the 7th dwarf (Score:5, Funny)
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Heigh-ho, Heigh-ho
(now I owe Disney royalties)
Imagine, a planet full of dwarfs (Score:5, Funny)
I must go there. I could be a giant in the getting things from high shelves industry.
Re: Imagine, a planet full of dwarfs (Score:2)
Let's call it Sneezy (Score:3)
Reminds me of my favorite T-shirt (Score:2)
PLUTO
Never Forget
1930-2006
https://www.amazon.com/Pluto-N... [amazon.com]
Dwarf planet no more (Score:2)
It's planet of short stature now
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...one way
imo more interestingly (Score:3, Interesting)
There's growing evidence for a ninth planet.* https://www.skyatnightmagazine... [skyatnightmagazine.com] (real stuff at https://arxiv.org/pdf/2504.172... [arxiv.org])
I've seen some vastly speculative bullshit (including still today "what if it's a micro black hole!?!!??!!?" which is fantastically unlikely, but the evidence does seem to be accumulating about a substantial TNO 500-700 au out.
*assuming the IAU doesn't again set up a bullshit scam-vote after nearly everyone left the conference to deprecate this one too.
"Evidence" you say? (Score:1)
We have better evidence that 20m votes were manufactured in 2020. [slashdot.org]
and as the typical #MAGAturd that you are, you fail to provide any counter arguments backed by your voluminous "evidence". #releaseTheEpsteinFiles
I was hoping they'd be able to find a new object (Score:2)
for the New Horizons probe to explore, like they did with the "snowman asteroid"*, but the area of space it can reach is rather limited, as it can change its path by only about a degree with the fuel it has left.
It's still amazing something going that fast can change its path by a whole degree. Due to luck, it didn't have to use much of its onboard fuel to get to its last 2 big targets. I hope it gets a chance to use it on something important.
* Found the by the Hubble scope, actually. They keep changing the
When do we get to vote oout the IAU (Score:2)
What are the other dwarf planets?
Is Mercury one?
Stop calling then "dwarf" planets! (Score:1)
That's offensive!!
They prefer to be called "little" planets.