Wood seems like a good choice for a satellite - it’s lightweight, easy to machine into different shapes, it’s cheap and readily available. It also doesn’t conduct heat as well as aluminum or steel, but I don’t know enough about building satellites to know if that’s a problem.
Because it is less ductile and flexible than aluminum or titanium. It’s easier to decommission by burning it up in the atmosphere without leaving particles behind, and if it collides with another object, it’s more likely to be obliterated.
Sure thing! In chemistry, an organic compound is anything that has carbon in it. Carbon dioxide, for example, is an organic compound. While organic compounds are what life is made of, they don’t necessarily come from life. Biological, in this context, would be something that’s part of a living thing.
If any actual chemists want to correct anything I’ve said wrong or expand on this that would be appreciated
Many hundreds of billions of dollars were paid to haul all of that mass up the gravity well into orbit. And guess who spent all of that money? And guess who’d like to make a LOT MORE money?
Apart from the spent rockets (now sitting at the bottom of Point Nemo) and fuel, most of ISS was clearly expensive and versatile and well-designed. And VERY likely to be worth recycling.
Instead, send a rocket up there to LIFT ISS into a stable parking orbit that won’t decay in thousands of years. By then somebody will have found a use for most of it. If ‘space-faring’ is really the goal, and not just a gimmick to put money into private pockets.
Using it to make a spectacular fireworks show is an ENORMOUS waste. The Egyptians didn’t dynamite the pyramids … a lucrative decision.
[Within the large group of rogue planets are 42 pairs of planets that are gravitationally bound together, something that’s never been observed before. ]
I wonder if that means all 84 planets are bound together.
Here is a quick summary. Astronomers used to assume that planets as big as 2x Earth diameter could be rocky planets. But now we know that most planets bigger than 1.3 Earth diameter are mini Neptunes. Although sometimes rocky planets can get as big as 1.5 Earth diameter.
Neptune’s diameter is about 50 megameters. Earth’s diameter is 12.7 megameters. So per the article, most planets bigger than a 16.5 megameter diameter is probably a mini Neptune. Although a rocky planet could be as big as a 19 megameter diameter.
Hm. Had a skim through the article and I hit this:
And it is unclear whether a spacecraft could even be launched successfully through the debris shell to enable travel to other planets. Humans would effectively be trapped on Earth by space junk, with multiple tonnes of vaporized metal being added to the upper atmosphere every day through re-entry^12.
This is a common misunderstanding of the scale of space and the scale of how much debris a "Kesseler syndrome" would entail. I checked the article referenced at the end and it was only in support of the "vaporized metal being added to the upper atmosphere" part of this statement, not the "trapped on Earth" line.
We would not be "trapped on Earth" by Kessler syndrome. The debris is only a problem for something orbiting within it, exposing it to continuous risk of collision for months or years on end. Simply passing through is very unlikely to damage a craft.
So an alarmist misunderstanding was inserted into the middle of this article without any reference backing it up, which makes me dubious about the rest of the article as well.
I’d have to read it more throughly, but the biggest annoyance with starlink is right after launch when they’re all clustered and super bright because they haven’t hit their normal positions. When you’re doing really long exposures, a satellite screaming through your field momentarily is easy enough to filter out those noisy frames.
Is light pollution from satellites great for earth based astronomy, no. Are they ruining astronomy like so much click bait leads you to believe, not in my opinion.
Different telescopes will have different impacts and separate from the direct trails general light pollution is absolutely a problem. The don’t build these things in the middle of no where for fun.
This isn’t a random science writer relaying a sci-fi conversation they had, it’s a respected astronomer with multiple publications in Nature.
The planet’s atmosphere would feature something akin to Earth’s water cycle, but instead with sand cycling between solid and gaseous states. From the hotter, lower levels of the atmosphere, with temperatures close to 1,000C, silicate vapour would rise up, cool and form microscopic grains of sand, too small to see. Eventually, these clouds of sand dust would become dense enough that they begin to rain back down to the lower layers of the atmosphere. Below a certain level, the sand would sublime back into vapour, completing the cycle.
“The clouds would be like a hazy dust,” said Decin. “And these sand particles are streaming around at extremely high velocity. A few kilometres per second.”
Jesus. That sand is raining down on you at like 6800kph/11,000mph if it’s 5km/s. Those water cutting machines barely reach 1km/s and they’re used to cut steel and titanium.
Some pretty interesting ideas. I was unaware that anything was living in the Atacama salt deposits, which certainly lends some credence to the idea that something could be pulling moisture out of the air on Mars, thin as it is.
I remember reading some article about deserts, and how, even when they seem completely empty of life, they actually have entire tiny fragile ecosystems living just under the sand. The article was in favor of imposing restrictions on dune buggies in a couple deserts where the activity was growing out of hand, because wherever the buggies went, that fragile ecosystem was just wiped out. And with the harsh conditions, it takes a really long time for them to recover.
Yeah, cryptobiotic crust! I’ve seen it in the Sonoran desert. It doesn’t look like much, I think if I hadn’t been warned ahead of time not to step on it I might have just done it without thinking. Given that just footprints can take on the order of decades to heal I think a dune buggy ban makes sense in areas where it grows.
I’m still surprised to learn about the microbes in the Atacama: it’s the driest place on earth, and I would have expected the salt deposits to make it even harder for anything to live there. Yknow what they say I guess: “Life, uh, finds a way.”
Not really. If more material falls in, its mass and size increases (the volume increases faster than the mass, which is why it’s so unexpectedly low density in the first place), but otherwise it just sort of sits there.
Over the very long term, it will evaporate away by Hawking radiation. But that’s a very very slow process. Like, long after everything else in the universe has ended.
That’s the thing about black holes that always blows my mind. I don’t understand how the larger a black hole is, the less dense that it is. In my mind, I always think of black holes as super dense objects containing so much matter in such a little space that the gravity is crazy strong. How can something so not dense be a black hole? It doesn’t make sense to me!
To be fair, the density is calculated from the event horizon, which is a somewhat arbitrary boundary. All the mass is still concentrated at the singularity which is still infinitely dense, just… a bit more so.
Ah, I didn’t realize that. I guess that’s a little more terrifying. Sounds like you could pass the event horizon and not be instantly crushed, but would have no way of ever escaping. You’d just eventually get sucked into the singularity.
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