If we are 1AU from the sun, and this planet is 90AU from the sun, then it is between 89 and 91 AUs from earth depending on the progress of our orbits (assuming perfectly circular orbits). So they did change the frame of reference.
This dwarf planet is 90 AU from US not from the sun. They just said that the dwarf planet is 90 AU away from us and that 1 AU is equal to the distance between the sun and the earth.
But since the dwarf planets orbit is extremely eccentric that varies heavily.
Ugh, didn’t read the “dwarf” part and got my hopes up for planet 9. When they eventually do find it they have to name it something with P so that the old mnemonics still work.
This far-flung orbit may be the result of an encounter with a giant planet, which ejected the candidate dwarf planet out of the solar system, say the researchers.
Poor guy. Hopefully he’s out there finding his own family.
At least it doesn’t have to deal with the toxicity Pluto does, being in the family one day and then coldly rejected from the family from the planet club the next. And we wonder why it’s exterior is frozen…
It turns out that for all of these different methods, you will find an extremely clear bimodal distribution that groups the 8 planets together as being highly capable of clearing their orbits whereas everything else falls into a statistically distinct non-clearing group. This is because there's sound dynamic reasons for why objects would fall into one group or the other with nothing lasting long in the "grey area" between them. Once an object becomes significantly better than its orbital neighbors at clearing the neighborhood it snowballs due to the feedback loop of scattering or absorbing its neighbors into itself.
That makes this a good criterion for classification. As the old saying goes, "cleave nature at the joints."
With Newtons law of gravity, there is a big, but seemingly solved problem that’s been known for a long time: things must not touch. Potential energy is calculated by dividing a term by the distance of two objects. You can’t devide by zero, so if the distance goes to zero, energy goes to infinity, which doesn’t make sense. The solution is to prevent the centers of mass of things from touching. This isn’t a problem, because in real life, masses aren’t points, but solid objects and the centers of mass are in the middle, so they can’t touch, because the outer parts collide first. And in simulations you can just make a rule that says no touching.
This kind of gap in a formula, where it stops being defined, is called a singularity in math. And to deal with them, you just have to know, when to expect them. For hundreds of years, people thought, collisions were the only singularities in Newtonian gravity. Easy to avoid, so not a problem. Now in this paper, they prove, that there are other, non-collission singularities and give an explicit example.
The arrangement in the picture has the middle mass going back and forth between the two binaries faster and faster and it reaches infinite speed in finite time. It basically leaves the universe, like a glitch in a video game. Also the reverse is allowed too: you just need the four masses from the two binary systems and there is nothing in Newtonian gravity that says a fifth mass can’t randomly appear from out of nowhere with infinite speed, slow down and settle between the too binaries.
Since only five masses were necessary to create this problematic constellation, it’s likely that there are many more possible.
Luckily, we have Einsteins theory of gravity now, so don’t have to worry about Newton too much. However, this does have its own, completely different kind of singularity, where the curvature of spacetime goes to infinity. People initially thought, that would be a problematic, unphysical behavior, like Newtons singularities, but it turns out that’s just a real thing that happens: black holes. Here the annoying singularities are mercifully shrouded in an event horizon, so at least we don’t have to look at them. Unless… But there is a solution for that too.
Given there are known polar planetary discs, and this orbit seems stable, wouldn't that suggest that polar systems are formed because of some past interaction between the two stars that disrupted them from the original plane of formation?
Possibly. I didn't dive in deeper to see if they even know the shape of the orbit. From my understanding a capture is very unlikely to have a near circular orbit. But planetary discs definitely aren't captures, so something changed the stars in those.
What I like about this image is that this is probably the biggest object that I can compare to something I know, that I can “comprehend”. With 6 km wide, it is about the same size as Grenoble, a city I have seen from above while hiking. I can understand how far the picture looks from it, how small a human would be on it
I think that !space is the most general community, and communities like “!astronomy” and “!spaceflight” are subsets.
Interesting data from a telescope? Astronomy and space, but not spaceflight.
A new GPS satellite is launched? Spaceflight and space, but not astronomy.
The Perseverance rover drills into a neat rock on Mars? Space, but not really astronomy or spaceflight.
A new space telescope is launched? Definitely all three.
These are just my thoughts though, and I’d love to hear what others think.
@Bee, @otter, @Bitswap Thoughts on changing the display name of !space from “Space & Astronomy” to just “Space”? Not that astronomy posts wouldn’t be welcome, but it could help reduce confusion with this community.
It looks like the icon and banner are broken, even on mander.xyz. @Bitswap, were you in the process of updating those? It could be a cross instance moderation issue. Otherwise how are these:
Neat to see a 6-7 solar mass black hole spotted. First one without a companion star to give it away! As we get better at finding black holes of this size, will be interesting to see if they end up explaining part of the “dark matter” problem.
astronomy
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