Recent comments in /f/space

BenZed t1_jaf0g0u wrote

Reply to Black holes may be quietly generating the force that is tearing the universe apart, experts say by dr_gus

So:

  • Gravity slows down time.
  • The higher the gravity a reference frame is subjected to, the slower time passes.
  • Black holes decrease the degree by which matter is evenly distributed throughout the galaxy universe by creating singularities from which matter can't escape

Maybe the expansion of the universe only appears to be accelerating because black holes are increasing the gradient by which time passes?

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theexile14 t1_jaf082x wrote

Reply to comment by myflippinggoodness in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

There are ideas about doing that with some gel type substance to capture junk. Unfortunately, a large metal object doesn't work as the collisions may occur at relative speeds of hundreds or thousands of km/hr. At that speed you mostly just smash things into pieces and send the careering all over. Unfortunately that hurts more than helps.

Also, that mass would be huge and cost a ton to put into orbit.

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dont_you_love_me t1_jaeyewe wrote

Reply to comment by Tjam3s in Black holes may be quietly generating the force that is tearing the universe apart, experts say by dr_gus

Cause in and of itself is a human concoction. You cannot actually prove that anything is caused within the universe. It could very well just be that the information we observe simply presents itself in a specific mandatory pattern and order and our brains totally fabricate the concept of causality.

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myflippinggoodness t1_jaey5bz wrote

Reply to comment by theexile14 in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

Ok, mby you're someone to ask about this: what if they put up like a big, heavy metal shield just to float around, let small shit smash into it, just so the small shit loses velocity and falls into LOW LEO so that it falls in like a couple years instead of a couple centuries?

Hopes like I'm 5 👌

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SteveMcQwark t1_jaex0wr wrote

Reply to comment by nednobbins in China to expand its space station, international astronaut selection underway by ye_olde_astronaut

On the one hand, you don't have gravitational loading for the most part (there's some because of various forces that get applied to a space station during operation, but not at the level you'd have on the ground). However, you can get structural oscillations which behave somewhat differently than they do on the ground, as well as various torques that get applied throughout operation. And because of weight considerations during launch, space structures are often made of aluminum, which doesn't have a fatigue limit, so it will weaken over time even for minor stresses. You hear about fractures being found in the walls of Russian ISS modules because of this. These effects get worse as you scale up a structure.

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Ok_Copy5217 OP t1_jaewp8p wrote

Reply to comment by austfraust in Col. David Scott — first man to drive on the Moon — comes to Jacksonville for award by Ok_Copy5217

Scott seems to be one of the more private moonwalkers in comparison to Buzz or Charlie Duke. He didn't show up to any recent space events and didn't publish memoirs

He did this talk on Apollo guidance computer in 1982

https://www.youtube.com/watch?v=NVHPunas4E4&t=316s

An interview from ten years ago

https://www.youtube.com/watch?v=2ygz1pWFgAo

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Adeldor t1_jaewmj7 wrote

Reply to comment by DBDude in Interesting take on SpaceX’s 2023 Revenue by KotesFolly_

A few months ago I had a go at calculating the annual costs of the currently operating satellites. It doesn't factor in launch pad and other non-recurring and standing costs, but it does give an idea. I repeat it below:

  • Currently ~3000 satellites at ~$250k each, and each lasting 5 years
  • One Falcon 9 launches ~50 satellites, at a marginal launch cost of $15,000,000 (used booster + fairings)

So, total launch cost is:

  • $250,000 * 50 + $15,000,000 = $27,500,000, or $550,000 per satellite
  • The satellites last 5 years, so the per year cost is $110,000 per satellite

Thus, for all 3000 satellites, the current annual cost to build and launch is ~$330,000,000.

Of course, they're adding satellites, version 2 is coming out, Starship will reduce marginal launch costs by maybe an order of magnitude, ground operations and development costs are not included here, blah blah blah. Nevertheless, this might give a glimpse of the expense side.

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Decronym t1_jaew36o wrote

Reply to We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

|Fewer Letters|More Letters| |-------|---------|---| |ASAT|Anti-Satellite weapon| |ESA|European Space Agency| |GEO|Geostationary Earth Orbit (35786km)| |GSO|Geosynchronous Orbit (any Earth orbit with a 24-hour period)| | |Guang Sheng Optical telescopes| |LEO|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |MEO|Medium Earth Orbit (2000-35780km)|

^(6 acronyms in this thread; )^(the most compressed thread commented on today)^( has 16 acronyms.)
^([Thread #8634 for this sub, first seen 28th Feb 2023, 22:55]) ^[FAQ] ^([Full list]) ^[Contact] ^([Source code])

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Adeldor t1_jaeuc70 wrote

Reply to comment by Am_Seeker_731 in We need more rules for space junk and moon bases, NASA and US officials say by DevilsRefugee

The Δv required to send anything from Earth orbit into the sun is far higher than that required to eject it from the solar system. Less Δv still is required to have it reenter the Earth's atmosphere. The practicalities of imparting the required velocities is, however, non-trivial.

To get an idea of the Δv required to get anywhere departing Earth - from the Sun to leaving the solar system - this map helps.

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