7 ms·

On the other hand a reentering ICBM warhead (test) looks like from the ground as if the gods are angry with you and your general vicinity: https://www.youtube.c

On the other hand a reentering ICBM warhead (test) looks like from the ground as if the gods are angry with you and your general vicinity: https://www.youtube.com/watch?v=2a1acYZ93yc https://www.youtube.com/watch?v=2a1acYZ93yc

pfdietz 3y ago
Notice the two that impacted at almost exactly the same spot, a few second apart (around 1:00). What precision!
- dylan604 3y ago
  Yeah, that was the first thing that popped into my mind as well when I saw that. Horse shoes and hand grenades, and atomic weapons was what we always joked about being close enough
- krisoft 3y ago
  Yeah. To understand why this is quite a flex: nearly no structure survives when they are directly hit with a nuclear weapon. The way hardened structures are designed is that the designers guestimate how big of a boom they have to survive and at what distance. They do this based on your intelligence sources of course. So let's say your spies are telling you that the enemy can deliver 60 kiloton device with 200m circular error probable (CEP). Then your engineers can calculate how likely is that your bunker/silo will survive that (and can do something like a counter attack.) And you build the number of silos you think you need based on that calculation. You put a lot of concrete and lot of work literally in the ground based on those numbers. And then suddenly your enemy just improves their guidance system and they drop (figuratively) such a video on you. That tends to cause jitters.
ericbarrett 3y ago
Awesome link. Reminds me that one of my biggest gripes with movies is that when they show meteors (or whatever) entering Earth, it's never at realistic speeds. They're always super slow and floaty, hovering in the sky to menacing effect. Great, that's the artist's choice. But the real thing is so much scarier, like this footage! And it's still a fraction of the speed of an interstellar object.
- marcosdumay 3y ago
  On movies those are usually very large objects. Very large objects do hoover menacingly for a very long time before they finally appear to fall for a few seconds. The larger it is, the longer it will stay hoovering and only slowly growing in size.
  - ericbarrett 3y ago
    Nah, even the big ones are shown sauntering through the atmosphere at maybe Mach 3, trailing smoke and flames like lit pitch. A city-sized asteroid wouldn't be more than a bright dot until the last seconds before entry, and at interstellar speeds it would take about three seconds to go from the vacuum of space to ground impact unless it had a very shallow vector.
    - pfdietz 3y ago
      At relativistic speeds it would take about 1 millisecond to go from LEO altitude to the ground.
      - buildbot 3y ago
        A relativistic asteroid would not be a good time for earth. Apparently according to gpt4 (so big grain of salt), a 1km asteroid going 0.9c is roughly 4.37×10^16 megatons of TNT worth of energy.
        szundi 3y ago
        Or a grain of TNT
        dylan604 3y ago
        that's one of those too big to comprehend type numbers. that's fine when talking about number of atoms, or the distances to another galaxy. trying to have my brain apply that to explosion just immediately goes to BSOD
wutwutwat 3y ago
"Peacekeeper" ICBM... the irony
- krisoft 3y ago
  How many did it kill?
  - wutwutwat 3y ago
    I'm not talking about the test. I'm talking about an entire missile system designed to deliver nuclear payloads to anywhere in the world being dubbed "Peacekeeper", but you already knew that.
    - krisoft 3y ago
      > I'm talking about an entire missile system designed to deliver nuclear payloads to anywhere in the world being dubbed "Peacekeeper" I'm also talking about the LGM-118 Peacekeeper missile system. It was in service from 1986 to 2005. Did it ever needed to be used in anger or not? During that time did any military attack the nation which fielded it? If not I would say it lived up to its name.
- runjake 3y ago
  Seeing as the Peacekeeper hasn't killed anyone, the name seems pretty apt. The US nuclear program is about deterrence after all. Well, after 1945, anyway.
  - wutwutwat 3y ago
    Weapon designed for use in a war or otherwise some sort of conflict requiring the use of lethal force, which would be the exact opposite of peace, is named peacekeeper These comments are being obtuse on purpose. Look at the name and look at what the name is on. The name peacekeeper is on a weapon that will only be used in times of no peace. Not a hard thing to see the irony in.
tomcam 3y ago
TIL the shockwave effect so popular in movies the last 20 years is 100% accurate
Terr_ 3y ago
On the subject of impressive old missile footage, I recommend the Nike-X program's Sprint interceptor-missile. Not hot glowing plasma on re-entry, but instead going up. As a short-range interceptor, Sprints were slammed up out of their silos via an explosively-driven piston, then they would ignite and reorient in midair, accelerating at 100g to reach Mach 10. The missile itself couldn't see very much, but would be remotely guided with strong signals from the launch installation. https://www.youtube.com/watch?v=gSFIkGfbLxs&t=23m37s https://www.youtube.com/watch?v=gSFIkGfbLxs&t=23m37s https://www.youtube.com/watch?v=6lWDbwmsz9E&t=7m15s https://www.youtube.com/watch?v=6lWDbwmsz9E&t=7m15s https://www.youtube.com/watch?v=3dl9Ovwmnxw&t=2m44s https://www.youtube.com/watch?v=3dl9Ovwmnxw&t=2m44s
runlevel1 3y ago
Here's footage of several MIRVs entering the atmosphere at night: https://youtu.be/3ZM3y5qpMgY?t=68 https://youtu.be/3ZM3y5qpMgY?t=68 On a more scientific note, here's a video from the Space Shuttle boosters as they reenter (2005): https://youtu.be/527fb3-UZGo?t=70 https://youtu.be/527fb3-UZGo?t=70

pfdietz 3y ago

Notice the two that impacted at almost exactly the same spot, a few second apart (around 1:00). What precision!

dylan604 3y ago
Yeah, that was the first thing that popped into my mind as well when I saw that. Horse shoes and hand grenades, and atomic weapons was what we always joked about being close enough
krisoft 3y ago
Yeah. To understand why this is quite a flex: nearly no structure survives when they are directly hit with a nuclear weapon. The way hardened structures are designed is that the designers guestimate how big of a boom they have to survive and at what distance. They do this based on your intelligence sources of course. So let's say your spies are telling you that the enemy can deliver 60 kiloton device with 200m circular error probable (CEP). Then your engineers can calculate how likely is that your bunker/silo will survive that (and can do something like a counter attack.) And you build the number of silos you think you need based on that calculation. You put a lot of concrete and lot of work literally in the ground based on those numbers. And then suddenly your enemy just improves their guidance system and they drop (figuratively) such a video on you. That tends to cause jitters.

ericbarrett 3y ago

Awesome link. Reminds me that one of my biggest gripes with movies is that when they show meteors (or whatever) entering Earth, it's never at realistic speeds. They're always super slow and floaty, hovering in the sky to menacing effect. Great, that's the artist's choice. But the real thing is so much scarier, like this footage! And it's still a fraction of the speed of an interstellar object.

marcosdumay 3y ago
On movies those are usually very large objects. Very large objects do hoover menacingly for a very long time before they finally appear to fall for a few seconds. The larger it is, the longer it will stay hoovering and only slowly growing in size.
- ericbarrett 3y ago
  Nah, even the big ones are shown sauntering through the atmosphere at maybe Mach 3, trailing smoke and flames like lit pitch. A city-sized asteroid wouldn't be more than a bright dot until the last seconds before entry, and at interstellar speeds it would take about three seconds to go from the vacuum of space to ground impact unless it had a very shallow vector.
  - pfdietz 3y ago
    At relativistic speeds it would take about 1 millisecond to go from LEO altitude to the ground.
    - buildbot 3y ago
      A relativistic asteroid would not be a good time for earth. Apparently according to gpt4 (so big grain of salt), a 1km asteroid going 0.9c is roughly 4.37×10^16 megatons of TNT worth of energy.
      - szundi 3y ago
        Or a grain of TNT
      - dylan604 3y ago
        that's one of those too big to comprehend type numbers. that's fine when talking about number of atoms, or the distances to another galaxy. trying to have my brain apply that to explosion just immediately goes to BSOD

wutwutwat 3y ago

"Peacekeeper" ICBM... the irony

krisoft 3y ago
How many did it kill?
- wutwutwat 3y ago
  I'm not talking about the test. I'm talking about an entire missile system designed to deliver nuclear payloads to anywhere in the world being dubbed "Peacekeeper", but you already knew that.
  - krisoft 3y ago
    > I'm talking about an entire missile system designed to deliver nuclear payloads to anywhere in the world being dubbed "Peacekeeper" I'm also talking about the LGM-118 Peacekeeper missile system. It was in service from 1986 to 2005. Did it ever needed to be used in anger or not? During that time did any military attack the nation which fielded it? If not I would say it lived up to its name.
runjake 3y ago
Seeing as the Peacekeeper hasn't killed anyone, the name seems pretty apt. The US nuclear program is about deterrence after all. Well, after 1945, anyway.
- wutwutwat 3y ago
  Weapon designed for use in a war or otherwise some sort of conflict requiring the use of lethal force, which would be the exact opposite of peace, is named peacekeeper These comments are being obtuse on purpose. Look at the name and look at what the name is on. The name peacekeeper is on a weapon that will only be used in times of no peace. Not a hard thing to see the irony in.

tomcam 3y ago

TIL the shockwave effect so popular in movies the last 20 years is 100% accurate

Terr_ 3y ago

On the subject of impressive old missile footage, I recommend the Nike-X program's Sprint interceptor-missile. Not hot glowing plasma on re-entry, but instead going up. As a short-range interceptor, Sprints were slammed up out of their silos via an explosively-driven piston, then they would ignite and reorient in midair, accelerating at 100g to reach Mach 10. The missile itself couldn't see very much, but would be remotely guided with strong signals from the launch installation. https://www.youtube.com/watch?v=gSFIkGfbLxs&t=23m37s https://www.youtube.com/watch?v=gSFIkGfbLxs&t=23m37s https://www.youtube.com/watch?v=6lWDbwmsz9E&t=7m15s https://www.youtube.com/watch?v=6lWDbwmsz9E&t=7m15s https://www.youtube.com/watch?v=3dl9Ovwmnxw&t=2m44s https://www.youtube.com/watch?v=3dl9Ovwmnxw&t=2m44s

runlevel1 3y ago

Here's footage of several MIRVs entering the atmosphere at night: https://youtu.be/3ZM3y5qpMgY?t=68 https://youtu.be/3ZM3y5qpMgY?t=68 On a more scientific note, here's a video from the Space Shuttle boosters as they reenter (2005): https://youtu.be/527fb3-UZGo?t=70 https://youtu.be/527fb3-UZGo?t=70