Most people don't know off-hand that Pluto is ~40-50AU from the sun, so 700AU is hard to conceptualize.
Side note: Apart from AU already being defined as average distance and not current distance, the distance referenced is how far out the proposed object is now, not its general orbital parameters. At that orbital distance 23 years of motion isn't going to be much change in distance even if it's in a hyperbolic orbit.
Hell, it's been nearly 2 decades since Pluto was itself planet 9. Just bringing the name up in a discussion about planets is going to cause more confusion.
The source we are discussing is space.com, a website which frequently mentions Star Wars and whose stated mission is to "transport our visitors across the solar system and beyond through accessible, comprehensive coverage of the latest news and discoveries." My comment was about communicating this research in a way that better fits "most readers" of space.com. If you think qualitative orrery models are beneath you and want to exclude those people, then you are not the target audience. Just go read the actual paper.
Or four days travel at the speed of light, to an outside observer. Or instantaneous for anyone travelling at the speed of light.
() Not really, I'm using artistic hyperbole.
Time units are more approachable than distances I will never cross.
https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_i...
~30-50AU if you are referring to the range of orbital distance.
Most people won't even have the slightest idea what 1 AU is. Most people know less about most topics (including space) than the original ChatGPT (3.5) did — probably only people who at least started a degree with a space sciences module are likely to know more than 3.5, and I expect plenty of space.com readers to be enthusiastic amateurs rather than professionals.
That said, I do I expect the average reader of space.com to know what an astronomical unit is, but even so I don't expect them to know the average orbital distance of Pluto.
But is even that assumption my quartz?
Or 698 trillion bananas.
But if you got “15x further than Pluto” you have context without needing to know any other trivia-style numbers.
Also it’s not like distance to Pluto is a meaningful number either since it’s extremely variable . AU at least is fixed
15x means no one alive today will see a mission that reaches the planet, and that's more accessible for most readers per above.
(9.5 * 15 / 3 = 47.5) + 30 years = 77.7 so some teenagers could live to see a probe reach it even without hypothetical life extension technology.
Warp 4 = 109 billion km/hr
Per https://i.imgur.com/Su1RB.jpeg
https://memory-alpha.fandom.com/wiki/Warp_factor also lists values in a couple charts that check out.
Then to show Planet 9 distance they have to get in a car and drive a few miles.
That worked for me.
It communicates the scales really well, while only taking up a little over a foot of bookshelf space when not being "navigated". I have two heavy metallic retro looking rocket bookends for it.
I wonder how could this object be counted as a "planet" belonging to the Solar system, even if it were the size of Jupiter. But it's an object "estimated to be 2 to 4 times the radius, and about ten times the mass of the Earth". This must be another class of celestial bodies, some jumbo-sized Oort cloud object.
Also depending how elliptical the orbit, is the perigee might be much closer than 700AU, while still being further than Pluto's orbit. For all we know 700 AU is the apogee and say the perigee is 70 AU (1.4x Pluto's apogee ).
The body must also be large enough to clear other bodies in the same orbit, except at the Trojan positions (L4 and L5), to be considered as a planet. Otherwise it would just be a Trans-Neptunian Object (TNO) or a Kuiper Belt Object (KBO) at these distances.
It obviously does in this case. But this pedantic detail is rather important. It was used to demote Pluto a few years back.
Does it? Would we actually know if there was another slightly more sparse belt at 700AU? If we can't track a large planet in that area, why would we be certain about the belt?
Alternatively, if it's an external object captured by the Sun, how would we even classify it as clearing or not if there's nothing to clear?
> how would we even classify it as clearing or not if there's nothing to clear?
I assume that it's based on mathematical modeling.
I guess I’d always put all the gas giants in the same “very, unimaginably big” bucket. I knew Jupiter was the biggest, then Saturn, but I didn’t realize just HOW big they were compared to the rest. At the risk of stating the very, very obvious, Jupiter is huge!!!
Masses of gas giants are: Jupiter, 317.8 earth mass; Saturn, 95.2 earth mass; Neptune, 17.1 earth mass; Uranus, 14.5 earth mass
[0] https://en.m.wikipedia.org/wiki/Earth_mass#Unit_of_mass_in_a...
10x earth masses usually implies a gas giant.
There is no way to capture with just 2 bodies - it would have to leave on gthe same hyperbolic orbit that it arrived on. However if it drove by and had a close enough interaction with a third body, like Jupiter, it could lose angular momentum to the planet, resulting in entering an orbit around the Sun. Further gravitational interactions with planets could then smooth that orbit out over time.
Alternately this could be the more straightforward scenario of interstellar object hits planetoid, they merge, and the new combined object is now in orbit.
You don't need complex reverse slingshot interactions. You just need a low enough relative velocity to not shoot off the other side.
I would expect this to be the norm for capture, not some exotic phenomenon.
A ball doesn't need to lose energy to be captured in a valley either.
You just apply a radial force to turn a line into a circle.
Anything that approaches the sun slower than escape velocity will be captured.
And the comment you're responding to already mentioned that other bodies can make a capture happen. Nobody was saying capture is impossible.
You could think of it as speeding up as it falls toward the sun, it then slows down by the exact same amount as it leaves the Sun.
In order to stay near the sun it needs to lose some of that speed, and given that momentum is conserved, the only possible way is to either hit the Sun or send that momentum to a third object.
It seems like the idea was to send a bunch of instruments way out and then take pictures in the brief time they were at a useful distance, but if there's a planet out there we can orbit and so stop the instruments at that distance it seems like we could make a permanent super telescope.
* 700 times further from the Sun than the Earth
* 15 times further from the Sun than Pluto
* 0.01 lightyear, or 1/400th the distance to the nearest star
Or, it's the difference between going for a 15 minutes walk and walking from Boston to Orlando (or San Diego to Seattle, for the West Coasters).
It's off by a factor of 8ish, which I applied to turn 2mph from a rate into a smaller unit of time but failed to balance.
It should have been an hour's walk (~2 miles) versus 700 hours' (~1400 miles).
Hutton Orbital is located approximately 6,784,404 light seconds, or 0.22 light years, so this will be 50 hours of non boosted SC.
I think you have an extra factor of 1000 somewhere.
Which means Hutton is a lot further actually.
700 further from the Sun than Earth is tangible as "really really far" though.
Pluto is a fairly unremarkable dwarf planet. I don’t think it really helps to compare things to it.
I don't need to sue you. It's just entirely incorrect by any sane definitions of a planet. It's not the further if you include similar bodies or not a planet. As I have no interest in saving American misplaced pride (because let's not kid ourself it's about anything else), I don't see the point of spreading misinformation.
> Because more people know about Pluto than Eris or Sedna
Only if you were born before it was retrograded which will be less and less likely as time goes on.
> My cosmological knowledge is above average, but I don't know off the top of my head if 700 AU is super-duper far away or still in the range of the gas giants.
I'm not convinced that giving it in multiple of the distance between Pluto and the sun is in any way more useful than distance between the Earth and the sun or that it helps conceptualise the distance relative to the gas giants.
Anyway, Pluto orbit is highly excentric so you have 20AU of wiggle room here when considering distance.
> Only if you were born before it was retrograded which will be less and less likely as time goes on.
I admit my age plays into it. Though I am curious about the role Pluto has in modern primary school, do you know? I understand that it now has the same technical status as Eris et al., but I think it's still a fantastic example of how scientific understanding develops and changes. Not on par with discarding heliocentricity, but a very practical example of ongoing changes still present in our own time.
> As I have no interest in saving American misplaced pride (because let's not kid ourself it's about anything else)
I don't understand how this ties into American pride (nor am I American), what did I miss?
Pluto was the only planet discovered by an American and most of the people who are extremely attached to it tend to feel that removing Pluto as a planet is somehow taking something away from the USA.
As far as I know, the topic barely exists at all in other countries.
Another perspective on the size of the solar system, like the Pale Blue Dot.
It could also allow gravity and Oberth effect acceleration of small probes to meaningful fractions of the speed of light for interstellar flyby missions. Imagine the Oberth effect boost from thrusting in such a deep gravity well.
We don't have enough data to see whether there are unexpected instabilities in detected planetary systems. But it would be an interesting project to look for those.
If the Moon were suddenly transformed into a tiny black hole with the same mass, it would continue to orbit the Earth at the same distance. Ocean tides due to its gravity would continue normally. There would not be much effect except that it would no longer be visible with the naked eye and would no longer reflect the sun's light back to Earth. If you found it in a telescope, you might see gravitational lensing as it passed in front of the star field. Objects like probes or old spacecraft stages orbiting the Moon would continue to do so.
The only danger would be that if things fell into it I suppose you might get dangerous X-ray and gamma ray emissions from its accretion disc that would be a problem at such a close range. That would not be an issue with a primordial black hole much further away.
If there were such an object we could send probes to orbit it and study it, and some experiments may involve firing objects or shooting lasers or beams of particles into it to attempt to learn about the quantum effects at the event horizon. This could be massive for physics, allowing us to access and observe conditions and energies not replicable here on Earth with any current technology.
BTW we don't have any hard evidence that primordial black holes exist, but many theories predict them. So far such predictions around black holes have a pretty good track record. If you made me bet, I would bet on them existing. They are a candidate for some or perhaps even all of dark matter, though even if that's not the case they might still exist. It's possible that the dark matter haloes we can spot with gravitational lensing are clouds of these things. ("Clouds" of course is a misnomer-- the distance between them would be many light years.)
If planet nine is a PBH it means that at some point one was captured by our solar system into a Kuiper Belt orbit. Even if planet nine isn't one, there still may be small asteroid mass PBHs in our solar system, so we still might find one. They would require extremely sensitive X-ray or gamma ray telescopes or highly accurate gravitational models of the solar system to detect.
Another visualization: if you had an Earth mass black hole with a solid shell surrounding it at the same radius as the Earth’s surface is from its core, gravity atop that shell would be 1g. The actual black hole would be about the size of a marble.
If you got close to it you would of course be subject to insane gravity and be “spaghettified” etc. All the mass would be in that marble. But at a distance it would be the same.
Compared to that object the Earth is mostly empty space. Ordinary matter is not that dense.
Black holes are totally fascinating. They are in some ways the most extreme objects that can possibly exist. If we could study one we could learn a lot.
Which is to say they are extremely high entropy.
There’s not enough matter nearby to feed it enough to form an accretion disc
> we could send probes to orbit it
Hitting a cm-sized black hole orbit at a lunar distance sounds insanely hard, given it’s invisible (even with occasional lensing).
A micro black hole traveling at tremendous velocity would go right through the Earth and keep going, but as it encountered the atmosphere it might emit a bunch of ultra high energy gamma rays (due to accretion) that set off fusion reactions and create an airburst. From there it would shoot right through the Earth and cause another kaboom when it exited, but that would have been in the middle of the Pacific. Nobody would have noticed in 1908.
https://en.wikipedia.org/wiki/Tunguska_event
No way of knowing unless we find evidence in the form of a "track" through layers of rock or some other signature. A comet or other similar body remains a more likely explanation for that event.
Let’s fire up a replica of TARS, load up ChatGPT inside (TARS-GPT, patent pending), and yeet it straight toward the Schwarzschild golf ball. It’ll narrate live.
Imagine the livestream:
“Approaching event horizon. Spaghettification at 3%. Mood: stretchy.”
“Entering gravitational lensing zone… wow, even my tokens are redshifting.”
Bonus: With the right timing and Oberth maneuver, TARS-GPT might sling itself into Alpha Centauri before we finish arguing whether Pluto’s a planet again.
Worst case: we lose a robot. Best case: we unlock quantum gravity and get a podcast from inside a black hole.
I'd call that a win.
Humor devolves the site into useless one liners. If you want evidence of that, go to reddit and see how useful that site is these days if you want to actually research and learn something. Slashdot knew this back in the day and while funny posts got visibility, they did not add anything to a user's total karma score.
As far as devolving into useless one liners --there is an emerging tech called the at-proto (not related to modems hahaa) that is poised to disrupt billions of dollars worth of sites like this one. Enjoy this era while it lasts..
Look at Xhitter for endless examples of this, basically the whole site now.
For all it's worth, there's no need to go black hole to explain the lack of visual observation. Objects that far from a star reflect very little if any light and would appear black to a black background.
If a black hole with a mass of, say, Ceres hit the Earth, it would not be particularly worse than if Ceres hit the Earth.
This equivalency is true for many aspects of orbital mechanics (depending on setup giving sufficient distance), but I don't believe that's true at all for a collision. Someone with more knowledge correct me, but a black hole with the mass of Ceres would be very tiny but also emitting a ton of radiation. The collision would be very different.
If the black hole had a mass more similar to a 0.5-mile asteroid...well, I'm not sure what would happen. Would it just punch a hole straight through the earth?
On the other hand taking 0.00016 of earths mass, turning it into a blackhole, and shooting it through the earth isn't likely to cause nearly the damage that Ceres (100x size of the dinosaur killing asteroid) ... unless you keep the velocity low enough that it stays inside the earth.
Domesticating fusion would be much easier. That is within sight.
https://arxiv.org/pdf/1909.11090
As I recall, it did not get printed this way because the ink would be too expensive, or mess with the paper.
That's the idea behind this paper (and similar ones like it): since they're looking for the planet's intrinsic emissions, from its internal heat, it's only a single inverse-square law.
With d being ~20 times Neptune's distance and ~140 times Jupiter's, these really are large factors!
Edit: with an accretion disk, I'd assume we'd have noticed it by now. Outside of that, as a black hole gets smaller, the hawking radiation wavelength should go down. It is rather weak overall, but it would be rather close. I haven't actually done the math, and, this is not my area of expertise. Would a relatively close by small black hole's hawking radiation be brighter than further X-ray emitters? Dunno.
The break even point for hawking radiation vs the cosmic background is about the mass of the moon.
I'm not going to do much more searching or calculation but I would be willing to bet a black hole small enough to emit xrays would have a remaining lifespan measured in nanoseconds at most.
A black hole bright enough to see its hawking radiation has to be tiny and would be quite short lived with an origin of unknown mechanism.
Depends on what distance you want to see it from.
A black hole that glows as hot as an incandescent filament would have as much mass as a 250km cube of rock and it would last for 10^35 years. It would have a radius of 60nm and emit less than a microwatt.
> a black hole small enough to emit xrays
To reach the low end of xrays, 100 electron volts, we'd need a black hole 100 times smaller. It would still have 10^29 years of lifetime, and would be emitting 2 milliwatts of xrays.
To reach the high end of xrays, 100k electron volts, we'd need a black hole 100k times smaller. It would still have 10^20 years of lifetime, and would be emitting 2 kilowatts of xrays.
To go the other way around, if I calculate a black hole that has "only" 10 billion years of lifetime left, weighing a dainty 190 million tons, it would be emitting 10 gigawatts of gamma rays. At 10 gigawatts of output, it would shrink by 1 ton every 285 years. The speed of light squared is an enormous number.
https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati...
Is my calculation correct?
https://bsky.app/profile/plutokiller.com/post/3lnqm2ymbd22r
If those two spots are the same object, that object is on a high-inclination orbit; but the pattern the Planet 9 hypothesis explains is only compatible with a low-inclination object.
You mean Eris? Pluto is ~10 times the mass of Ceres.
Seriously though, is he one of the people responsible for Pluto's demotion to dwarf planet?
Back in the early 1800s children used to memorize the names of the 12 planets: Mercury, Venus, Earth, Ceres, Pallas, Juno, Vesta, Mars, Jupiter, Saturn, Uranus, and Neptune. But then in 1845 astronomers discovered Astraea, and now there were 13. In 1847 three more were discovered: Hebe, Iris, and Flora. Then Metis, Hygiea, Parthenope, and Victoria by 1850. The 100th asteroid was discovered in 1868, and the pace only got quicker from there. Somewhere along that line people started using the words “asteroid” and “asteroid belt” and schoolchildren were mercifully spared the pointless task of memorizing hundreds, and later many thousands, of names of asteroids.
The same thing happened to Pluto. Just as Ceres was the first discovered asteroid, Pluto was the first discovered TNO. There are now hundreds of named TNO and thousands more that are just numbered. Nobody should force schoolchildren to memorize them all. Just tell them that there are an unknown number of objects in the Kuiper belt and the Oort cloud and they’ll know as much as they need to know. Give them bonus points if they know the names Ceres and Pluto, and more if they know why these two were discovered first of all the objects in their class: they’re the biggest. Otherwise there’s nothing special about them.
Or just tell them that there's an unknown number of planets in the solar system, but the big 8 are the only ones they're expected to memorize. That was actually the original plan by the IAU, and how many (I believe most) planetary scientists define planet today.
The decision being based mainly on not wanting to add newly discovered planets to the list of planets in the solar system always rubbed me the wrong way. As is the tendency for people to mistakenly believe that this is settled science, when it's actually an unsettled nomenclature debate.
Non native english speaker here, but last I checked further was a metaphorical distance, when farther was a literal distance. You can push a concept further, but you walk farther right? Or did I miss something?
Sure, we wouldn't be able to get there for many decades, but "within a century" would be feasible.
There are so many unknowns surrounding the nature of black holes. Having one in our backyard would give us a chance to test our guesses.
(Aside: time dilation already occurs on and around Earth. GPS satellites have to account for the fact that time runs ever so slightly slower on the ground.)
I thought that since you could get into areas where the field was arbitrarily intense, that it would be able to provoke significant relativistic effects.
I had assumed that the small mass would make tidal forces more problematic than with a larger one, but if the distance/intensity of the field isn’t a factor, but only the overall mass… wouldn’t that mean that we could utilize black holes at arbitrarily long distance to provoke those effects, so it would just be a universal constant based on the mass of the universe, and there would be no relativistic effects on a relative basis?
What am I missing here?
However with an earth max black hole you could get closer, which would have a higher acceleration, and would time dilate more strongly.
By comparison the entire Kuiper belt – including Pluto – is estimated to have a total mass of about 10% of Earth's mass.
https://science.nasa.gov/universe/exoplanets/exoplanet-disco...
Of course, all of this comes with the caveat that nothing like this may exist yet. Sealed mass ecosystems exist in glass jars, but something on the scale of a ship is going to be an entirely different ballgame.
Here is a nice graphic that excludes Ceres https://en.m.wikipedia.org/wiki/Dwarf_planet#Population_of_d...
The motivation for this dwarf planet nonsense was to try to keep the official planet list small so children could memorize them with ease, but that is absurd. We do not remove countries from the map to make it easier for children to learn geography and there are over 100 of them.
The list was stable at 12 for about 40 years, but started growing again in the middle of the century. By 1868 there were 100 named asteroids. Not a single one has people living on it, so making children memorize their names was seen as a waste of time. Teach them about the asteroid belt and then move on to more important things. Likewise with the TNO: teach them about the Kuiper belt and the Oort cloud and then move on to more important things. No need to make them memorize Pluto, Haumea, Makemake, Gonggong, Quaoar, Sedna, and Orcus, nor any of the hundreds of other named TNO.
Nonsense. "Pluto is grandfathered in as a planet, nothing else is a planet". See?
By the way, the loss of atmosphere takes millions of years too. The popular "we must restart mars magnetic field" trope likes to omit the fact. In the end occassional replenishment of volatiles would probably be cheaper.
Was earth not a planet shortly before and after collision with Theia?
The naming pedantry seems ridiculous given that we have such a small sample size.
To steal a quote: All definitions are wrong. Some are useful.
Hell, what's it called now? Jupiter's orbit is shared with millions of Trojans. Many of them are more than a hundred kilometers in diameter; for reference, Deimos, one of Mars' moons, has a mean radius of about 6 km.
To discover Planet 9, simply open your ephemerides and look for "Neptune".
