IANAP, but isn’t universal expansion understood to be accelerating? How would “weakening forces of nature” account for that? Assuming this energy could be “lost” (breaking an even longer standing and well tested principle of physics), that loss wouldn’t accelerate anything. At best the speed would remain neutral.
The tired light theory is an alternative explanation to the red shift of distant light that says it’s not because distant objects are all moving away from us but instead that the light somehow loses energy as it travels, which lowers its frequency.
There was another alternate theory that suggested everything was shrinking instead of the universe expanding (thus wavelengths seem longer by the time they get to us).
Personally, I’m more “open to the idea” than “sold” for the idea of the universe’s accelerated expansion. I like theories that eliminate the need for dark matter or energy, especially given that the current ones requiring them assume that they make up 95% of everything. It just seems more likely that we don’t understand things as well as we do than to assume we’re right about everything we think but just need to add 19 times what’s already here to balance it all out.
This thing is just a mosaic of ordinary CCDs. I’m sure the name has something to do with it’s specific scientific goals, but that’s not explained at all in this article. They didn’t even attempt to make any kind of connection between the veil and dark energy. Or even between supernovae and dark energy.
It feels like the title should be “uninhabited”. Life on earth doesn’t survive because we continue to be bombarded with nutrient carrying asteroids, it just needed them to kick it off. That few nutrients are likely to make it from the surface to the ocean means the genesis is unlikely to occur, but it doesn’t seem to make a decision about whether an unlikely genesis could survive, even if only in a small pocket of the ocean.
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.
Starlink is causing problems, but it seems to me that this image was made in bad faith to oversell the case. The caption says it’s a combination of 29 separate exposures, but if those exposures were combined properly, you wouldn’t see the satellites (median combination does wonders, and there are more sophisticated techniques which do even better). Some streaks start at one chip edge and extend to another chip edge, without continuity across the focal plane. So it’s not at all clear just how this image was created. And why on earth is it not flat-fielded? Maybe this is just really sloppy image processing, but even amateurs can do far better than this, leaving the final combination with no satellites at all.
Looks pretty damn cool, but supersonic commercial flights will be ridiculously expensive, pollutive and wasteful, there’s no going around this. There’s zero practical uses for the common man.
Astronomy: “a natural science that studies celestial objects and the phenomena that occur in the cosmos”
I suppose anything that happens in the universe is technically “a phenomenon that occurs in the cosmos” but this seems more suited to !nasa, which could definitely use the content. Would you consider posting it there as well?
I’m not the biggest fan of Lemmyworld, I prefer thematic instances such as Mander.xyz. Maybe we can consider this community as broader than strict astronomy?
I also prefer thematic instances, but try to find appropriate communities within those instances. Just because it’s coming from NASA, doesn’t make it astronomy.
Depending on which aspects of the project you think are important and want to discuss there are a few communities here that might be relevant.
Earth Science includes environment, and environmental impact seems to be the most popular talking point so far.
Noise and other forms of pollution are public health issues and there is a local community for that, although I’m not sure it’s really a great fit there.
Physics might be another choice due to the fact that a lot of physics is going into the engineering of something that reduces sonic booms.
Or maybe you just need to find the right thematic instance. For example, I’m registered on slrpnk for my climate, energy efficiency, and anarchism fixes.
astronomy
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