The polarisation of the broadband emission shows the flux density of two orthogonal polarisations is anti-correlated with temporally shifting spectral structure observed.
Much more likely is that the galaxies will zoom relatively close to each other – say, a little under 500,000 light years away.
In To Sleep In A Sea Of Stars by C. Paolini, there is a group that aims to prevent or circumvent the heat death of the universe, although the post-human civilisation has barely touched a few star systems (<30 ly). In a similar fashion, I recommend to take the necessary steps to build up a galaxy defense force soon.
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.
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.
Very interestingly, they found that systems with fewer planets tend to exit their “ejection” phase after about 100 million years, but systems with 10 planets are still unstable even after a billion years. They also found that these more bountiful systems actually eject the majority of their planets, losing 70 percent after a billion years. Most of the ones ejected are lower-mass, as expected.
Wonder how many sibling planets we had when our solar system first formed. This sort of topic is always fascinating to me.
I’ve heard it can be hard to see with the naked eye, and it seems like it would probably get murdered by city lights. Something like some low power, wide-lens binoculars might help collect enough light to make it visible. Also, I’ve heard that cell phone cameras and cameras in general are pretty good at picking up the Aurora over the naked eye, especially on longer exposures.
Sounds about right. The main problem is getting our somewhere dark, where the horizon is visible. There are buildings for miles around, and its really cold because of the winds. I’ve got so many good excuses. I’m glad you have a long list of objects to look for. Its quite impressive, to be honest. I know my way around, but still not that many DSO’s off the top of my head 🙌
astronomy
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