8 ms·

If you’re doing 2e8 m/s, your ship is long and thin with a 1m3 nose cone, and space has 100 baseballs per m3 then you’re being hit by 2e10 baseballs a second.

by heads 3y ago

If you’re doing 2e8 m/s, your ship is long and thin with a 1m3 nose cone, and space has 100 baseballs per m3 then you’re being hit by 2e10 baseballs a second. How do I get an idea for what 20 billion baseballs (2TJ) feels like? Apparently bullets are about an order of magnitude more energetic than baseballs (800J vs 80J) so I guess I could try to build my intuition based on being shot ~2 billion times a second instead. A kiloton of TNT is 4GJ, so it’s also like a 500 kiloton bomb going off every second. Dropping 5e5kg of rock into the worlds biggest dumpster truck at 10m/s yields 25MJ of chaos so it’s also like a parking lot of 80,000 of those being filled with a continuous stream of rubble. That’s probably the best analogy given that we’re talking about machinery — your spaceship needs to have the build resilience of tens of thousands of dumpster trucks but condensed into the cross sectional area of a dinner table.

kaashif 3y ago
> A kiloton of TNT is 4GJ, so it’s also like a 500 kiloton bomb going off every second. Funnily, my first reaction to this comparison is that it makes it seem more plausible to me that this is possible. After all, a Star Destroyer can take gigaton level hits! But the problem with that is Star Destroyers are fictional. I've been spending too much time on spacebattles.com.
- heads 3y ago
  The numbers are big but they don’t seem “big big” like Sagittarius A* is big or the distance to Andromeda is big.
  - lstodd 3y ago
    Distance to Andromeda isn't big. Galaxy filaments are big.
- MilStdJunkie 3y ago
  The canon energy levels given for Star Wars weaponry are so inconsistent with the presentation that one either ignores canon or accepts that the Star Wars galaxy has fundamentally different physics. Extreme geek caution: I've been running a Star Wars pen and paper RPG since . . oh dear. . 2015, in an ancient simulationist[1] game system, and the only way I've been able to make anything consistent is dialing everything down to WW2 levels. 7.62x5X, .50 BMG, 46 cm/45 Type 94 capital ship weapons. All except for exceptional plot items, like lightsabers and doomsday weapons, which behave . . well, they're magic. Sensors are likewise pretty primitive, enhanced with canon exotics like Kronau radiation, so engagement ranges are (relatively) piddling, hostiles zip by each other all the time. Electronics and technology in general must be barely understood by literally anyone, with the powerful assemblies - hyperdrive cores, droid motivators, repulsorlift "sand" - being exotics, possibly xenotechnology from the deep past mined by xenoarchaeologists[2], but hooked together by varying degrees of "competent 1950s electrician". In short, it's a fantasy setting with guns that players get excited about. And a community of worldbuilders that is, let's not dice words here, insane. That second point is huge if you're not 24 or otherwise gifted with a combination of hubris and spare time. [1] All the kids today with their streamlined narrative-focused games! Seriously, though, I get it. The physics simulationist in me that brings me to HERO System says more about me as a person than my players. [2] Archaeology a much more valuable degree in the Star Wars universe.
  - ben_w 3y ago
    Your description reminds me of Star Fleet Battles. As a young teen I made the mistake of treating SFB like Star Trek, while also making the mistake of not realising that Star Trek itself was just doing space combat as ${year of filming}-era naval battles with latex and lightbulbs. SFB is 1900-1945 naval warfare, but themed with every plot point from TOS and TAS and probably some novels too, so has the Kzinti, Tholian webs, Klingon stasis field generators, and two distinct weapons where the TV series uses just photon torpedoes.
khazhoux 3y ago
> How do I get an idea for what 20 billion baseballs (2TJ) feels like? In the 90s, the show Special Relativity’s Funniest Home Videos would often have guys getting hit in the crotch 20B times with a baseball. Honestly, it never gets old.
- mattmaroon 3y ago
  They all started to look staged after the first billion though.
soco 3y ago
There we go again, Americans using anything but the metric system :) scnr
- kreeben 3y ago
  >> baseball How large is one of those, even? I much prefer to work with perfectly spherical Olympic swimming pools.
  - AlexAndScripts 3y ago
    Would that be the original British Imperial SOP or the closely-related but not-quite-the-same American SOP?
    - db48x 3y ago
      Actually, the American SOP is the original because the British changed the definition of the gallon in 1824, which you will notice is long after the Revolutionary War. No one in America cared, so we kept on using our customary units.
- heads 3y ago
  I’m British with, funnily enough, a Duke’s County cricket ball on my desk. My nephew is Californian and I gave him one for his sixth birthday. Mine felt a bit lighter so we did an experiment over Zoom together to measure the density. He’s certainly a bit young for that — “it’s the same size but yours is heavier” — but there’s no harm in influencing them from an early age. Of relevance to your comment: I made a point of doing it in grams and millimetres.
TheOtherHobbes 3y ago
It's clearly not a solvable problem with current ideas about technology. No amount of ice, rock, magnetism, or Magic Unobtanium is going to make this practical. I'm not even sure about warp drives. Bending spacetime one way means it has to squish back the other way. The energy released might not affect the ship - possibly - but I'd be surprised if it didn't affect the spacetime it had just passed through. Some kind of new physics might make all of this possible, but - by definition - we have no idea what that might be.
- kypro 3y ago
  Am I wrong to think it seems probable that such things aren't realistically possible given the fact that the universe seems to be so lifeless? If the practical limits of rocket technology don't allow life to much beyond their own solar system then given the vastness of space that would be a good reason why we don't see any evidence of intergalactic civilisations or large feats of engineering. All other explanations for why the universe seems to lifeless seem to rely on elaborate hypotheticals like us being an early civilisation, us being extremely lucky/improbable in other ways, or that alien life is anti-social. But it always seemed to me that the best explanation is probably just that such things are not possible. I mean there's a chance there's some new physics out there, but you'd think if there was star wars level tech out there (warp drives, etc) then something out there would have built one already and would rather quickly spread outwards...
  - tim333 3y ago
    It seems reasonable, although we may still be able to send messages with radio, lasers etc. Though even that isn't easy.
  - adrianN 3y ago
    Sending humans across thousands of light years seems almost impossible , but sending von Neumann probes throughout the galaxy should be possible with some reasonable improvement to our technology.
    - 3y ago
canadianfella 3y ago
[dead]
greggsy 3y ago
Could you repeatedly send disposable ‘dozer’ drone ships towards your destination to help clear the way, and potentially devise a means of keeping the clearing free of stray atoms?
- bufferoverflow 3y ago
  No, interstellar atoms (or other particles) aren't static, they aren't just hanging in one place. Everything is moving. Some particles are moving very fast.

by heads 3y ago

kaashif 3y ago

> A kiloton of TNT is 4GJ, so it’s also like a 500 kiloton bomb going off every second. Funnily, my first reaction to this comparison is that it makes it seem more plausible to me that this is possible. After all, a Star Destroyer can take gigaton level hits! But the problem with that is Star Destroyers are fictional. I've been spending too much time on spacebattles.com.

heads 3y ago
The numbers are big but they don’t seem “big big” like Sagittarius A* is big or the distance to Andromeda is big.
- lstodd 3y ago
  Distance to Andromeda isn't big. Galaxy filaments are big.
MilStdJunkie 3y ago
The canon energy levels given for Star Wars weaponry are so inconsistent with the presentation that one either ignores canon or accepts that the Star Wars galaxy has fundamentally different physics. Extreme geek caution: I've been running a Star Wars pen and paper RPG since . . oh dear. . 2015, in an ancient simulationist[1] game system, and the only way I've been able to make anything consistent is dialing everything down to WW2 levels. 7.62x5X, .50 BMG, 46 cm/45 Type 94 capital ship weapons. All except for exceptional plot items, like lightsabers and doomsday weapons, which behave . . well, they're magic. Sensors are likewise pretty primitive, enhanced with canon exotics like Kronau radiation, so engagement ranges are (relatively) piddling, hostiles zip by each other all the time. Electronics and technology in general must be barely understood by literally anyone, with the powerful assemblies - hyperdrive cores, droid motivators, repulsorlift "sand" - being exotics, possibly xenotechnology from the deep past mined by xenoarchaeologists[2], but hooked together by varying degrees of "competent 1950s electrician". In short, it's a fantasy setting with guns that players get excited about. And a community of worldbuilders that is, let's not dice words here, insane. That second point is huge if you're not 24 or otherwise gifted with a combination of hubris and spare time. [1] All the kids today with their streamlined narrative-focused games! Seriously, though, I get it. The physics simulationist in me that brings me to HERO System says more about me as a person than my players. [2] Archaeology a much more valuable degree in the Star Wars universe.
- ben_w 3y ago
  Your description reminds me of Star Fleet Battles. As a young teen I made the mistake of treating SFB like Star Trek, while also making the mistake of not realising that Star Trek itself was just doing space combat as ${year of filming}-era naval battles with latex and lightbulbs. SFB is 1900-1945 naval warfare, but themed with every plot point from TOS and TAS and probably some novels too, so has the Kzinti, Tholian webs, Klingon stasis field generators, and two distinct weapons where the TV series uses just photon torpedoes.

khazhoux 3y ago

> How do I get an idea for what 20 billion baseballs (2TJ) feels like? In the 90s, the show Special Relativity’s Funniest Home Videos would often have guys getting hit in the crotch 20B times with a baseball. Honestly, it never gets old.

mattmaroon 3y ago
They all started to look staged after the first billion though.

soco 3y ago

There we go again, Americans using anything but the metric system :) scnr

kreeben 3y ago
>> baseball How large is one of those, even? I much prefer to work with perfectly spherical Olympic swimming pools.
- AlexAndScripts 3y ago
  Would that be the original British Imperial SOP or the closely-related but not-quite-the-same American SOP?
  - db48x 3y ago
    Actually, the American SOP is the original because the British changed the definition of the gallon in 1824, which you will notice is long after the Revolutionary War. No one in America cared, so we kept on using our customary units.
heads 3y ago
I’m British with, funnily enough, a Duke’s County cricket ball on my desk. My nephew is Californian and I gave him one for his sixth birthday. Mine felt a bit lighter so we did an experiment over Zoom together to measure the density. He’s certainly a bit young for that — “it’s the same size but yours is heavier” — but there’s no harm in influencing them from an early age. Of relevance to your comment: I made a point of doing it in grams and millimetres.

TheOtherHobbes 3y ago

It's clearly not a solvable problem with current ideas about technology. No amount of ice, rock, magnetism, or Magic Unobtanium is going to make this practical. I'm not even sure about warp drives. Bending spacetime one way means it has to squish back the other way. The energy released might not affect the ship - possibly - but I'd be surprised if it didn't affect the spacetime it had just passed through. Some kind of new physics might make all of this possible, but - by definition - we have no idea what that might be.

kypro 3y ago
Am I wrong to think it seems probable that such things aren't realistically possible given the fact that the universe seems to be so lifeless? If the practical limits of rocket technology don't allow life to much beyond their own solar system then given the vastness of space that would be a good reason why we don't see any evidence of intergalactic civilisations or large feats of engineering. All other explanations for why the universe seems to lifeless seem to rely on elaborate hypotheticals like us being an early civilisation, us being extremely lucky/improbable in other ways, or that alien life is anti-social. But it always seemed to me that the best explanation is probably just that such things are not possible. I mean there's a chance there's some new physics out there, but you'd think if there was star wars level tech out there (warp drives, etc) then something out there would have built one already and would rather quickly spread outwards...
- tim333 3y ago
  It seems reasonable, although we may still be able to send messages with radio, lasers etc. Though even that isn't easy.
- adrianN 3y ago
  Sending humans across thousands of light years seems almost impossible , but sending von Neumann probes throughout the galaxy should be possible with some reasonable improvement to our technology.
  - 3y ago

canadianfella 3y ago

[dead]

greggsy 3y ago

Could you repeatedly send disposable ‘dozer’ drone ships towards your destination to help clear the way, and potentially devise a means of keeping the clearing free of stray atoms?

bufferoverflow 3y ago
No, interstellar atoms (or other particles) aren't static, they aren't just hanging in one place. Everything is moving. Some particles are moving very fast.