5 ms·

> Based on the images and video provided observers, the object’s diameter is estimated at 20 meters (ft). A 20 meter object created a fireball that could be ob

> Based on the images and video provided observers, the object’s diameter is estimated at 20 meters (ft). A 20 meter object created a fireball that could be observed from earth?

Gravityloss 5y ago
Yeah, stood out as surprisingly small. Jupiter diameter is about 140,000 km so isn't that flash at hundreds of kilometers across? I got 21 pixels while the planet is 500 pixels so 21*14000/500 = 588 km . Blurring might expand it though so in reality could be smaller. Tunguska was estimated 50-60 m diameter though I guess velocity could tend to be higher at Jupiter? https://en.wikipedia.org/wiki/Tunguska_event https://en.wikipedia.org/wiki/Tunguska_event
- Gravityloss 5y ago
  Nobody spotted the error? 21*140000/500=5880 km
jiggawatts 5y ago
Jupiter's high gravity likely meant that it hit at a greater velocity than it would have if it impacted Earth. As a rule-of-thumb, asteroids hit at or above escape velocity. Earth's is 11 km/s, Jupiter's is 60 km/s. Energy is the linear product of mass, but quadratic product of velocity. Hence, the ratio of an impactor's energy hitting Jupiter vs Earth is not 6:1, but 36:1. Mind you, this is nothing compared to what happens if even a mere pebble hits a neutron star!
- dhimes 5y ago
  I think the proper energy to calculate is that of an object falling into the Sun, being intercepted in its fall by the object it impacts.
  - jaggederest 5y ago
    Solar escape velocity near Jupiter orbit is only around 18km/s which is quite a bit less than Jupiter's own escape velocity.
  - lumost 5y ago
    Objects aren’t falling into the sun from infinity, as gravity decays according to an inverse square law the sun imparts relatively little kinetic energy to a Jupiter impactor relative to Jupiter.
    - dhimes 5y ago
      To match the calculations by JPL/NASA, assume that the objects are falling into the Sun from infinity.
- kamaal 5y ago
  >>Mind you, this is nothing compared to what happens if even a mere pebble hits a neutron star! What would happen if a pebble hit a neutron star? I'd like to imagine the pebble would vaporize at contact or even before it(temperature/radiation etc)? EDIT: https://en.wikipedia.org/wiki/Neutron_star https://en.wikipedia.org/wiki/Neutron_star The neutron star's gravity accelerates infalling matter to tremendous speed. The force of its impact would likely destroy the object's component atoms, rendering all the matter identical, in most respects, to the rest of the neutron star.
  - jiggawatts 5y ago
    The escape velocity of a Neutron star is comparable to a black hole, so something like 1/2 of the speed of light. So a 10 gram pebble hitting a Neutron star releases about the same energy as a 100 ton asteroid hitting Jupiter.
- samstave 5y ago
  Does something like that burn up in whatever Jupiter's atmosphere is? Are we seeing the flash of it burning up? or? What impact would something which was 20ft in diameter do to the earth?
- omegalulw 5y ago
  > As a rule-of-thumb, asteroids hit at or above escape velocity At first I was like what the fish but with just a lil bit of thought you realize how intuitive this is. Pretty cool.
tegeek 5y ago
Objects move pretty fast in space, usually tens of kilometers per second. A 20 meter of diameter object with velocity of 10000 mps is pretty deadly impact from Earth's point of view.
- WJW 5y ago
  Not really, the https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor was 20 meter diameter and hit the atmosphere at about 20 km/s. While there were some ~1500 injured people, the Earth as a whole did not really notice.
  - filoeleven 5y ago
    How much does the angle of impact come into play?
  - chongli 5y ago
    From your link: 400-500 kilotons of TNT I don’t know about you but I’d consider a Hiroshima-scale explosion pretty deadly. We just got lucky it didn’t hit the middle of a major population centre at a more direct angle. That could have been catastrophic.
    - WJW 5y ago
      It would suck to be in the area, yes. But the comment I was responding to said "pretty deadly impact from Earth's point of view." Hiroshima-scale explosions don't make an appreciable dent in the Earth itself, and any human population outside immediate vicinity will still be fine.
MrWiffles 5y ago
I wondered the same thing. 20 meters is about ~65 feet, just a little bit longer than a standard semi truck and trailer you might see out on the highway that’s hauling say, groceries. So my first thought was, “what kind of material would be that combustible to impact something at Jupiter’s size and leave that big a flash lasting 2 whole seconds?” Someone else commented about the size of the flash relative to Jupiter itself and my understanding of that persons comment was that the flash was about 10 times the diameter of the object give or take a little. So 20 meters made a ~200 meter visible explosion. Now somebody correct me if I’m wrong here since I most likely am, but isn’t Jupiter a gas giant? Meaning what we saw either detonated before hitting the surface, or what we saw was only the light from the impact explosion that made it through the gas/atmosphere layer above it at the point of impact. If the latter, the actual visible yield would have been higher than what we saw, right?
- rbanffy 5y ago
  In order to be visible, the flash must have happened above the top cloud layer. The surface is well below that - Jupiter is mostly atmosphere, with a little bit of extremely compressed planet in its middle.
- stan_rogers 5y ago
  "Combustible" doesn't matter. Nor, really, does "impact" in the sense of one objectively solid body striking another objectively solid body. Think Chelyabinsk - the actual "thing hitting the ground" impact was a relative nothingburger, and all of the excitement happened at altitude.
- dragonwriter 5y ago
  > Meaning what we saw either detonated before hitting the surface Since last I heard the understanding waa Jupiter probably does not have a solid surface to hit at all, “before” should probably be “without”.
bandyaboot 5y ago
I’m confused, what does the “(ft)” mean? Did they just forget to put a number there?
- samstave 5y ago
  Fused Tachyons.

> Based on the images and video provided observers, the object’s diameter is estimated at 20 meters (ft). A 20 meter object created a fireball that could be observed from earth?

Gravityloss 5y ago

Yeah, stood out as surprisingly small. Jupiter diameter is about 140,000 km so isn't that flash at hundreds of kilometers across? I got 21 pixels while the planet is 500 pixels so 21*14000/500 = 588 km . Blurring might expand it though so in reality could be smaller. Tunguska was estimated 50-60 m diameter though I guess velocity could tend to be higher at Jupiter? https://en.wikipedia.org/wiki/Tunguska_event https://en.wikipedia.org/wiki/Tunguska_event

Gravityloss 5y ago
Nobody spotted the error? 21*140000/500=5880 km

jiggawatts 5y ago

Jupiter's high gravity likely meant that it hit at a greater velocity than it would have if it impacted Earth. As a rule-of-thumb, asteroids hit at or above escape velocity. Earth's is 11 km/s, Jupiter's is 60 km/s. Energy is the linear product of mass, but quadratic product of velocity. Hence, the ratio of an impactor's energy hitting Jupiter vs Earth is not 6:1, but 36:1. Mind you, this is nothing compared to what happens if even a mere pebble hits a neutron star!

dhimes 5y ago
I think the proper energy to calculate is that of an object falling into the Sun, being intercepted in its fall by the object it impacts.
- jaggederest 5y ago
  Solar escape velocity near Jupiter orbit is only around 18km/s which is quite a bit less than Jupiter's own escape velocity.
- lumost 5y ago
  Objects aren’t falling into the sun from infinity, as gravity decays according to an inverse square law the sun imparts relatively little kinetic energy to a Jupiter impactor relative to Jupiter.
  - dhimes 5y ago
    To match the calculations by JPL/NASA, assume that the objects are falling into the Sun from infinity.
kamaal 5y ago
>>Mind you, this is nothing compared to what happens if even a mere pebble hits a neutron star! What would happen if a pebble hit a neutron star? I'd like to imagine the pebble would vaporize at contact or even before it(temperature/radiation etc)? EDIT: https://en.wikipedia.org/wiki/Neutron_star https://en.wikipedia.org/wiki/Neutron_star The neutron star's gravity accelerates infalling matter to tremendous speed. The force of its impact would likely destroy the object's component atoms, rendering all the matter identical, in most respects, to the rest of the neutron star.
- jiggawatts 5y ago
  The escape velocity of a Neutron star is comparable to a black hole, so something like 1/2 of the speed of light. So a 10 gram pebble hitting a Neutron star releases about the same energy as a 100 ton asteroid hitting Jupiter.
samstave 5y ago
Does something like that burn up in whatever Jupiter's atmosphere is? Are we seeing the flash of it burning up? or? What impact would something which was 20ft in diameter do to the earth?
omegalulw 5y ago
> As a rule-of-thumb, asteroids hit at or above escape velocity At first I was like what the fish but with just a lil bit of thought you realize how intuitive this is. Pretty cool.

tegeek 5y ago

Objects move pretty fast in space, usually tens of kilometers per second. A 20 meter of diameter object with velocity of 10000 mps is pretty deadly impact from Earth's point of view.

WJW 5y ago
Not really, the https://en.wikipedia.org/wiki/Chelyabinsk_meteor https://en.wikipedia.org/wiki/Chelyabinsk_meteor was 20 meter diameter and hit the atmosphere at about 20 km/s. While there were some ~1500 injured people, the Earth as a whole did not really notice.
- filoeleven 5y ago
  How much does the angle of impact come into play?
- chongli 5y ago
  From your link: 400-500 kilotons of TNT I don’t know about you but I’d consider a Hiroshima-scale explosion pretty deadly. We just got lucky it didn’t hit the middle of a major population centre at a more direct angle. That could have been catastrophic.
  - WJW 5y ago
    It would suck to be in the area, yes. But the comment I was responding to said "pretty deadly impact from Earth's point of view." Hiroshima-scale explosions don't make an appreciable dent in the Earth itself, and any human population outside immediate vicinity will still be fine.

MrWiffles 5y ago

I wondered the same thing. 20 meters is about ~65 feet, just a little bit longer than a standard semi truck and trailer you might see out on the highway that’s hauling say, groceries. So my first thought was, “what kind of material would be that combustible to impact something at Jupiter’s size and leave that big a flash lasting 2 whole seconds?” Someone else commented about the size of the flash relative to Jupiter itself and my understanding of that persons comment was that the flash was about 10 times the diameter of the object give or take a little. So 20 meters made a ~200 meter visible explosion. Now somebody correct me if I’m wrong here since I most likely am, but isn’t Jupiter a gas giant? Meaning what we saw either detonated before hitting the surface, or what we saw was only the light from the impact explosion that made it through the gas/atmosphere layer above it at the point of impact. If the latter, the actual visible yield would have been higher than what we saw, right?

rbanffy 5y ago
In order to be visible, the flash must have happened above the top cloud layer. The surface is well below that - Jupiter is mostly atmosphere, with a little bit of extremely compressed planet in its middle.
stan_rogers 5y ago
"Combustible" doesn't matter. Nor, really, does "impact" in the sense of one objectively solid body striking another objectively solid body. Think Chelyabinsk - the actual "thing hitting the ground" impact was a relative nothingburger, and all of the excitement happened at altitude.
dragonwriter 5y ago
> Meaning what we saw either detonated before hitting the surface Since last I heard the understanding waa Jupiter probably does not have a solid surface to hit at all, “before” should probably be “without”.

bandyaboot 5y ago

I’m confused, what does the “(ft)” mean? Did they just forget to put a number there?

samstave 5y ago
Fused Tachyons.