Astronomy and space exploration

hoom said:
Yeah, I mean probably Soviets have dropped the most bits of rockets on other countries being they launched most of their rockets overland from Kazakhstan.
But the US has done a pretty large amount of dropping bits of rockets on not just other countries but plenty on itself...

Here for example is a more balanced article from a few years back https://phys.org/news/2018-04-satellite-earth-week-average.html


I dunno wtf that video purports to show but if the shot with the building in the foreground & possibly sound of kids is from a school that booster landed a good km or 2 away from it, the debris appears to be in wooded area on a hillside, presumably the one in the distance from the 'school' shot.
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I dont know about that video, but it is true that they do not have a stellar record about worrying about negative externalities from their space activities. Times have changed since the 1970s in terms of expectations.
 
I believe what separates this from other pieces of space junk is its the largest in 30 years (hmm what about mir?, which I did try to see when it came crashing to earth early 2000s got up went to the beach in NZ looking north to hopefully catch a glimpse of it falling but saw nothing)
Is they could of choose where to crash land it (usually in the south pacific away from land, there was a recent stuff you should know podcast about this IIRC) but they didnt, they choose to let it fall anywhere.
The USA does stuff that I dont like eg musks lets triple the satellite count so we can have some internet for a few ppl around the world and has blown up a setlitte in the past (something that china done a couple of years ago)
 
If it is the largest in thirty years then it is clear they care less than other countries and pretending otherwise is silly. BTW that was the last one they let fall randomly. It landed in ivory coast. Then they decided to do the same again. They also showed toxic residue all over their own people at launch though are changing that .
 
Except its obviously not the biggest bit of space junk in 30 years.
Mir was 129tons, Challenger 78, the Ivory coast booster was last year not 30 years ago.
 
hoom said:
Except its obviously not the biggest bit of space junk in 30 years.
Mir was 129tons, Challenger 78, the Ivory coast booster was last year not 30 years ago.
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Yes I mentioned Mir, So I looked into it a bit more
https://www.space.com/china-rocket-falling-from-space-dont-worry
"Every few months, there's some small piece of space debris that gets found on the ground, but we haven't had this kind of 20-ton object re-entering uncontrolled for 30 years, until the Chinese started their 5B launches," McDowell said.
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One of the largest spacecraft ever to re-enter Earth's atmosphere remains the massive Mir space station, which was deorbited by Russia on March 23, 2001.
Mir's re-entry was a completely controlled descent aimed at disposing of the iconic Russian space station in the Pacific Ocean
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So I think what they are only talking about when they say largest in the last 30 years is in the 'deliberately gonna crash somewhere and we dont give a shit' category
This is not picking on China cause its China doing it, if it was the USA or any other country it would be just as bad. Hoon if ppl don't protest about China doing this, then they will keep on doing it in the future, yes the odds of this hurting anyone are astronomically small, then again the one last year damaged human structures in the Ivory Coast, which is also very small (Im guessing human made structures make up way less than 1% of the planets surface)

edit:
https://en.wikipedia.org/wiki/List_of_reentering_space_debris
 
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Theyve lost track of it. should be over south spain in 15 mins Im gonna have a look outside, in the faint chance its there
 
Debris from a large Chinese rocket, the Long March 5B, landed in the Indian Ocean near the Maldives, China’s space administration said.
 
yes disappointing I saw nothing, like mir 20 years ago (at least then I had beer), not sure how accurate the following is cause it most likely left debris over a path not just a specific point.
I should of stayed in bed but one never knows, I did see that comet from a couple of months ago, that was lame, nearly as lame as haleys comet (nothing can top that for a lame space event)
816
 
Voyager spacecraft detects 'persistent hum' beyond our solar system (microsoftnewskids.com)
May 12, 2021
NASA's Voyager 1 launched on September 5 1977, from Cape Canaveral, Florida, aboard a Titan-Centaur rocket, just weeks after its sister craft, Voyager 2. Although they were initially designed to last five years, more than 43 years after they launched, the crafts are still sending back data as they explore interstellar space.
...
Instruments aboard Voyager 1, which has moved past the edge of the solar system, through the solar system's border with interstellar space, known as the heliopause, and into the interstellar medium, have detected the sounds of plasma waves, according to research published Monday in the journal Nature Astronomy.

After entering interstellar space, Voyager 1's Plasma Wave System instrument detected oscillations in the gas, which is caused by our sun. But researchers also noticed that in between those eruptions, there was a steady and persistent signature.

"It's very faint and monotone, because it is in a narrow frequency bandwidth," Stella Koch Ocker, a Cornell University doctoral student in astronomy, said in a statement. "We're detecting the faint, persistent hum of interstellar gas."
...
Voyager 1 is the most distant human-made object in space and continues to function, despite its age and distance.
"Scientifically, this research is quite a feat. It's a testament to the amazing Voyager spacecraft," Ocker said. "It's the engineering gift to science that keeps on giving."
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sound (unlike the electro magnetic spectrum) must travel through matter
and yes there is about 1 atom per cm cubed in space but surely thats not enuf to transfer sound.

I would assume they dont mean sound, but they mention a hum and sound hence my confusion?

my theory is hendrix, Im not sure how, but its hendrix
 
If it's a plasma then the atoms are ionized and will couple with the local magnetic field. If I remember my Plasma Physics 101 basically what happens is that the motion of the magnetic field influences the motion of the ions, and the motion of the ions influences the motion of the magnetic field. So you can easily get oscillatory (wave-like) phenomena, which is kind of like sound but also kind of not.

For a press release a "hum" is something most people will understand at some level.
 
The different landing approaches between the US and China are interesting. China avoided the sky crane and landed a table with a ramp. Wonder where the mass trade off between the two is?

The sky crane is presumably a bit more mass efficient but it's is barmy.
 
Question that will ponder you... can light create a venturi effect... if seen through the fluid dynamics of gravity...?
 
Davros said:
If I'm understanding your question then the quick answer is no, because light wont accelerate
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Hey what about a superluminal boom, cherenkov radiation from particles exceeding the speed of light on a medium? Lights travels at 2.25E8 m/s in water an 3E8 in vacuum. How does it change speed if it doesn't accelerate :) also since it has no mass the acceleration would be infinite so instant change. But it is really absorbed by material and then re-emitted so that is less fun.


The venturi effect is about changing energy I think, the speed increases so pressure goes down. Light changes frequency so energy is changing, but I don't know which other bucket that energy goes to in a given reference frame.
 
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