I always thought of our universes as just a bubble, with dark matter all around us. It’s not the edge of the existence as much as the edge of our bubble.
We might not be the only bubble, but it’s impossible to interact or even observe them. Could be millions, could just be us. No way to every know.
Our bubble keeps expanding, until the edges aren’t dense enough to displace whatever’s out there. And we’ll either slowly fade and future civilizations will assume the universe has always shrunk. Because that’s all they’ve ever seen. Like if the human lifespan was a single minute, people would freak out everytime it approaches dawn or dusk. Not understanding that it’s a cycle.
The team’s measurements even suggest that the supernovae that virtually cleared the bubble of space in which the Milky Way resides was born in a cluster of stars within the Radcliffe Wave.
Wait, the Milky Way is inside of a bubble generated by novae which were inside a cluster which is inside the Radcliffe Wave which is… itself… inside the Milky Way?
The Radcliffe Wave formation is a bunch of gas that is apparently, wiggling, in incredibly huge time and distance scales, like a sinusoidal wave.
So, imagine very, very long ago, before the Milky Way formed, you have a particular dense gaseous region/formation.
Dense gaseous regions tend to give birth to new stars. This region did so, and then one of them supernova’d.
Next, the Milky Way ended up forming in the void created by this supernova.
Then, this dense gaseous region was basically incorporated into the Milky Way (seems like one of its spiral arms) over another absurdly long period of time.
But, for some reason, it is wiggling, in a manner that dense gaseous regions have not been observed to behave in.
Thats the best I can do here, I am not an astrophysicist, though I did take two quarters of intro level astronomy in college lol.
Probably worthwhile to note that the article says that their data ‘suggests’ not ‘shows’ or ‘proves’ the bit about the supernova clearing the Milky Way void.
To actually prove that would encompass, among many other things, running the clock backward on star orbits/trajectories over billions of years using extremely complicated models and mountains of data I am absolutely not qualified to comment on.
Im just trying to very broadly explain the chain of events here if this supernova really did cause the void the Milky Way formed in.
Anyway, other fun fact: Our Milky Way Galaxy is not actually a pure spiral Galaxy as it has so often been depicted for quite a long time.
It is actually a barred spiral galaxy. Basically, instead of just swirly arms, there are actually short, more or less straight parts to the arms as they emanate out from the center, which then begin to curve into spirally arms.
In an update posted on Sunday (Feb. 18), ESA said that the rentry ERS-2 is expected to take place on Wednesday (Feb. 21) at 10:19 a.m. ET (1519 GMT), plus or minus around 19 hours. This uncertainty is due to the “influence of unpredictable solar activity, which affects the density of Earth’s atmosphere” and can therefore change how much drag pulls on the satellite on its way down, ESA wrote.
Plus or minus 19hrs due to the sun’s effect on the density of the atmosphere. Mind blown.
There will be millions of applicants for this. They’ll get the cream of the crop for this experiment. If we ever end up actually going to mars then these people will be in every history book.
I don’t know all of the details of this mission, but it seems like they’ve just lowered the lowest point in its orbit - called periapsis - until it sits low enough in the atmosphere to get enough drag that the orbit slowly decays over a decade.
The lowest part of the orbit would only drop a little bit, but the highest part of the orbit woukd reduce more with each orbit. If you do it slowly enough, the orbit would circularise and then it would begin to decay more evenly. As it falls deeper into the atmosphere the orbit would decay faster and faster until it can no longer sustain orbit, and then it falls deeper into the atmosphere and burns up in just a few minutes.
The reason for this I can only guess at - it wouldn’t take a whole lot more fuel to just deorbit all at once. My best guess is that it has something to do with reentering at the lowest possible speed. If you fall from a high orbit and reenter, you have a lot more speed and have to dissipate more energy all at once. It’s possible this increases the risk that the satellite will fail to deobrit, and break up and send pieces off in less predictable orbits. If it breaks up from a low circular orbit, there’s no chance of any parts escaping back into orbit.
astronomy
Gorące
Magazyn ze zdalnego serwera może być niekompletny. Zobacz więcej na oryginalnej instancji.