5 ms·

From the simulation you linked looks like it is passing closeish to the Mars... but I do know that space is big. However, I am curious of what would happen if a

From the simulation you linked looks like it is passing closeish to the Mars... but I do know that space is big. However, I am curious of what would happen if an object of this magnitude hit mars at 90km/s.

ddahlen 1y ago
I would recommend staying on Earth...
jl6 1y ago
Assuming it’s at the upper range of the size estimate above, and of average rocky density, the kinetic energy of the impact would be something like a 10 billion megaton nuke. If we could steer it to hit one of Mars’s poles, it might do a bit of terraforming for us!
- eesmith 1y ago
  Where did my math go wrong? I got about 50,000 megatons. Assuming the high-end of 22km and a rocky/metallic density of 5000 kg/cubic meter (and assuming it's a cube): kinetic energy = 1/2 m v**2 = 1/2 * size * density * v**2 = 1/2 *(22000 m)**3 * (5000 kg/m**3) * (90 m/s)**2 / (4.184E15 J/megaton) = 52,000 megaton If it's an icy comet then the density is more like 500 kg/cubic meter, or 1/10th that number.
  - nandomrumber 1y ago
    1040 x more energy that the Tsar Bomba. Or 5-ish Tsar Bomba per country on Earth. Or 3466 Hiroshima nukes. Or 17 Hiroshima nukes per country.
    - nandomrumber 1y ago
      In light of the error in the parent comments math, I retract my previous comment and substitute the following bit of awkward silence: …
      - defrost 1y ago
        We all make mistakes, as the Dalek said climbing off the dustbin. FWiW .. here's mine (or is it?) One Tsar Bomba ~ 50 megatonne. One Hiroshima bomb ~ 15 kilotonne. One Tsar Bomba ~ 50,000 / 15 ~ 3,333 Hiroshima bombs. 1,040 x Tsar Bomba ~ 3,466,667 Hiroshima bombs.
        nandomrumber 1y ago
        Oops. Every time I see your username I can’t help but say it in my mind as Defrost Kelly, some kind of frozen Dr. Leonard "Bones" McCoy
        dalke 1y ago
        Imagine how I feel every time I see "Dalek" instead of my surname.
  - ars 1y ago
    90 m/s? Way too slow, it's more like 70km/s (or 90) - seems you left out a k.
    - eesmith 1y ago
      Yes, that was my error - thanks!
  - perihelions 1y ago
    I can not confirm this; the parent calculation is the correct one. I can't immediately find what your error was. (edit: It's your [km/s]—you wrote [m/s] by mistake). (let* ((ρ ([g (cm -3)] 5)) (d ([km] 22)) (m (* ρ (expt d 3))) (v ([km (s -1)] 90)) (ke (* 1/2 m (expt v 2))) (kg-tnt ([J (kg -1)] 4.2e6))) (values (/ ke kg-tnt) (as [megaton] (/ ke kg-tnt)))) 5.133857142857142e19 [KG] 5.133857142857143e10 [MEGATON]
    - eesmith 1y ago
      My mistaken use of m/s instead of km/s, in a squared term, indeed gives a HUGE difference. Thanks!
  - Voultapher 1y ago
    Based on the corrected 90 km/s instead of m/s it should be 52 pt (peta-ton) impact.
    - eesmith 1y ago
      Let's see if I get this math right. Mauna Loa is about 95,000 km3 in volume says https://www.usgs.gov/volcanoes/mauna-kea/science/geology-and-history-mauna-kea https://www.usgs.gov/volcanoes/mauna-kea/science/geology-and... . Density of TNT is 1.6g/cm3: 95000 km3 * (1000m/km)**3 * 1600 kg/m3 = ~1.5E17 = 150 pt. 1/3rd of the mountain in TNT. Nope, I can't conceive of that much energy.
- nativeit 1y ago
  …and after just a few million years to settle down again, we’ll be ready to visit blue sky on Mars!
nandomrumber 1y ago
Would be wild if a sufficiently large object with a lot of water and organic molecules hit Mars, ejected a lot of material in to Mars’ orbit to then go on to form a sufficiently large moon that tidally massaged Mars’ core to cause a dynamo to generate a sufficiently strong magnetic field to… Terraform Mars!
- WithinReason 1y ago
  You don't need a magnetic field to terraform Mars, it can hold onto an atmosphere without it for 100M years.
  - nandomrumber 1y ago
    Without a magnetic field, isn’t the surface of Mars subject to sterilising radiation from Sol?
    - cyberax 1y ago
      Planetary magnetic field only weakly protects against cosmic rays (extra-solar origin). A thick enough atmosphere will stop pretty much all the charged particles from the normal solar radiation.
    - jajko 1y ago
      If it would be so bad, Earth's polar regions (experiencing aurora borealis) would be inhabitable too. Earth's magnetic field is not magically neutralizing all charged particles from the Sun, just diverts them (some maybe away, but many simply towards poles). And clearly even our mag field (and Sun's heliosphere) is not enough to shield us from those crazy cosmic rays.
- noduerme 1y ago
  in a somewhat related story, I was on a beach in Costa Rica last week, watching some spider monkeys in a palm tree trying to whack open small nuts. Just then, an American family walked up the beach with two teenage boys. They didn't notice the monkeys I was watching. But one of the boys grabbed a coconut off the sand and became determined to break it open with a rock in front of his parents. So watching the monkeys and the boy simultaneously, I had the distinct feeling of how slowly evolutionary, let alone geological, processes actually move.
ReptileMan 1y ago
Absolutely nothing. Way too small and slow.
- nativeit 1y ago
  How fast does something need to be traveling before you’d consider it to be fast? It probably weighs as much as a city and it is traveling tens of times faster than a high-velocity bullet.
  - ReptileMan 1y ago
    It is of the same caliber as the dinosaur ending meteorite. The planet barely shrugged from it. There is suspicion that something the size of pluto has already hit mars once upon a time. And it is way more massive than this speck of cosmic dust.

ddahlen 1y ago

I would recommend staying on Earth...

jl6 1y ago

Assuming it’s at the upper range of the size estimate above, and of average rocky density, the kinetic energy of the impact would be something like a 10 billion megaton nuke. If we could steer it to hit one of Mars’s poles, it might do a bit of terraforming for us!

eesmith 1y ago
Where did my math go wrong? I got about 50,000 megatons. Assuming the high-end of 22km and a rocky/metallic density of 5000 kg/cubic meter (and assuming it's a cube): kinetic energy = 1/2 m v**2 = 1/2 * size * density * v**2 = 1/2 *(22000 m)**3 * (5000 kg/m**3) * (90 m/s)**2 / (4.184E15 J/megaton) = 52,000 megaton If it's an icy comet then the density is more like 500 kg/cubic meter, or 1/10th that number.
- nandomrumber 1y ago
  1040 x more energy that the Tsar Bomba. Or 5-ish Tsar Bomba per country on Earth. Or 3466 Hiroshima nukes. Or 17 Hiroshima nukes per country.
  - nandomrumber 1y ago
    In light of the error in the parent comments math, I retract my previous comment and substitute the following bit of awkward silence: …
    - defrost 1y ago
      We all make mistakes, as the Dalek said climbing off the dustbin. FWiW .. here's mine (or is it?) One Tsar Bomba ~ 50 megatonne. One Hiroshima bomb ~ 15 kilotonne. One Tsar Bomba ~ 50,000 / 15 ~ 3,333 Hiroshima bombs. 1,040 x Tsar Bomba ~ 3,466,667 Hiroshima bombs.
      - nandomrumber 1y ago
        Oops. Every time I see your username I can’t help but say it in my mind as Defrost Kelly, some kind of frozen Dr. Leonard "Bones" McCoy
        dalke 1y ago
        Imagine how I feel every time I see "Dalek" instead of my surname.
- ars 1y ago
  90 m/s? Way too slow, it's more like 70km/s (or 90) - seems you left out a k.
  - eesmith 1y ago
    Yes, that was my error - thanks!
- perihelions 1y ago
  I can not confirm this; the parent calculation is the correct one. I can't immediately find what your error was. (edit: It's your [km/s]—you wrote [m/s] by mistake). (let* ((ρ ([g (cm -3)] 5)) (d ([km] 22)) (m (* ρ (expt d 3))) (v ([km (s -1)] 90)) (ke (* 1/2 m (expt v 2))) (kg-tnt ([J (kg -1)] 4.2e6))) (values (/ ke kg-tnt) (as [megaton] (/ ke kg-tnt)))) 5.133857142857142e19 [KG] 5.133857142857143e10 [MEGATON]
  - eesmith 1y ago
    My mistaken use of m/s instead of km/s, in a squared term, indeed gives a HUGE difference. Thanks!
- Voultapher 1y ago
  Based on the corrected 90 km/s instead of m/s it should be 52 pt (peta-ton) impact.
  - eesmith 1y ago
    Let's see if I get this math right. Mauna Loa is about 95,000 km3 in volume says https://www.usgs.gov/volcanoes/mauna-kea/science/geology-and-history-mauna-kea https://www.usgs.gov/volcanoes/mauna-kea/science/geology-and... . Density of TNT is 1.6g/cm3: 95000 km3 * (1000m/km)**3 * 1600 kg/m3 = ~1.5E17 = 150 pt. 1/3rd of the mountain in TNT. Nope, I can't conceive of that much energy.
nativeit 1y ago
…and after just a few million years to settle down again, we’ll be ready to visit blue sky on Mars!

nandomrumber 1y ago

Would be wild if a sufficiently large object with a lot of water and organic molecules hit Mars, ejected a lot of material in to Mars’ orbit to then go on to form a sufficiently large moon that tidally massaged Mars’ core to cause a dynamo to generate a sufficiently strong magnetic field to… Terraform Mars!

WithinReason 1y ago
You don't need a magnetic field to terraform Mars, it can hold onto an atmosphere without it for 100M years.
- nandomrumber 1y ago
  Without a magnetic field, isn’t the surface of Mars subject to sterilising radiation from Sol?
  - cyberax 1y ago
    Planetary magnetic field only weakly protects against cosmic rays (extra-solar origin). A thick enough atmosphere will stop pretty much all the charged particles from the normal solar radiation.
  - jajko 1y ago
    If it would be so bad, Earth's polar regions (experiencing aurora borealis) would be inhabitable too. Earth's magnetic field is not magically neutralizing all charged particles from the Sun, just diverts them (some maybe away, but many simply towards poles). And clearly even our mag field (and Sun's heliosphere) is not enough to shield us from those crazy cosmic rays.
noduerme 1y ago
in a somewhat related story, I was on a beach in Costa Rica last week, watching some spider monkeys in a palm tree trying to whack open small nuts. Just then, an American family walked up the beach with two teenage boys. They didn't notice the monkeys I was watching. But one of the boys grabbed a coconut off the sand and became determined to break it open with a rock in front of his parents. So watching the monkeys and the boy simultaneously, I had the distinct feeling of how slowly evolutionary, let alone geological, processes actually move.

ReptileMan 1y ago

Absolutely nothing. Way too small and slow.

nativeit 1y ago
How fast does something need to be traveling before you’d consider it to be fast? It probably weighs as much as a city and it is traveling tens of times faster than a high-velocity bullet.
- ReptileMan 1y ago
  It is of the same caliber as the dinosaur ending meteorite. The planet barely shrugged from it. There is suspicion that something the size of pluto has already hit mars once upon a time. And it is way more massive than this speck of cosmic dust.