Asteroid hits moon → moon hits Earth possible?

  • #51
I know this thread is a bit old, but I was wondering if anyone could answer a couple questions about the effects such a scenario would have on Earth. I understand that it is completely speculative, but I am curious to know.

1. Would Earth experience any specific effects of an impact of an asteroid with the moon? If so, what would they be?

2. As the moon careens toward Earth, what specific type of effects would Earth experience?

3. As the moon enters the atmosphere of the Earth, what specific types of effects would Earth experience?
 
  • #52
DaveC426913
Gold Member
19,099
2,615
I know this thread is a bit old, but I was wondering if anyone could answer a couple questions about the effects such a scenario would have on Earth. I understand that it is completely speculative, but I am curious to know.
No asteroid would be large enough to have such an effect on the Moon as you describe. It would have to be a small planetoid.

A planetoid of that size would be big nough to perturb the Moon's orbit around Earth and Earth's orbit around the Sun.

1. Would Earth experience any specific effects of an impact of an asteroid with the moon? If so, what would they be?
It would shower the Earth with debris, most of which would burn up in the atmo.
2. As the moon careens toward Earth, what specific type of effects would Earth experience?
If we are talking a collision powerful enough to virtually stop the Moon in its orbit, then we'd have a pulverized Moon. That's the only way the Moon could end up on a direct collision course with Earth.

No, what is by far the more plausible scenario is that the asteroid perturbs the Moon and puts it in a decaying orbit bound to eventually collide with the Earth after dozens, hundreds or millions of orbits.
3. As the moon enters the atmosphere of the Earth, what specific types of effects would Earth experience?
Just Google "Earth Impact" for some awesome pix. You can deduce the effects.
[PLAIN]http://coolflowerspics.info/pictures/flowers/images/82/earth-impact1.jpg [Broken]
 
Last edited by a moderator:
  • #53
No, what is by far the more plausible scenario is that the asteroid perturbs the Moon and puts it in a decaying orbit bound to eventually collide with the Earth after dozens, hundreds or millions of orbits.
Is that like Mars' moon? Wouldn't that take a very long time to happen? What could speed up the process, maybe increase the velocity of the orbit?

I have seen many specials about what would happen if objects strike the Earth. I was fascinated to learn that there is so much more than I originally thought. For example, if a large enough asteroid impacts the Earth, I had no idea that it could raise the global temperature or set the atmosphere on fire. From what I can gather, there are specific zones of destruction, time tables, and specific angles that alter the outcome. These are the specifics that I am still learning.

Would the gravity of the moon (on its way towards the Earth) affect Earth's oceans? Tectonic activity? Electro-magnetic field?
 
  • #54
DaveC426913
Gold Member
19,099
2,615
Is that like Mars' moon? Wouldn't that take a very long time to happen? What could speed up the process, maybe increase the velocity of the orbit?
Actually, increasing the velocity of the orbit would keep the moon at a distance. To cause the impact to happen sooner, you'd decrease the velocity.


I have seen many specials about what would happen if objects strike the Earth. I was fascinated to learn that there is so much more than I originally thought. For example, if a large enough asteroid impacts the Earth, I had no idea that it could raise the global temperature or set the atmosphere on fire.
Wellllll "set the atmosphere on fire" is a loose term. "on fire" literally means to oxidize. The air is already oxygen and inert nitrogen, so thte atmosphere would not be set on fire. However yes, it would get so hot that things would burn and even vapourize.

From what I can gather, there are specific zones of destruction, time tables, and specific angles that alter the outcome. These are the specifics that I am still learning.
Would the gravity of the moon (on its way towards the Earth) affect Earth's oceans? Tectonic activity? Electro-magnetic field?
Sure, but so what? That's like asking if, just before your car is totaled in a front-end collision, would the initial effects ruin your headlights and crush your bumper.

I guess if it happened slow enough, we'd get smaller effects before the end. Definitely very high tides. Shores for hundreds of miles inland would be washed out. Volcanism and earthquakes would start tearing the crust apart. When the Moon got close enough (within Earth's Roche limit) the Moon would fragment into a ring of debris. As this spread out around the planet, effects would actually even out somewhat (though it is unlikely there would be any survivors at this point or any ground for them to stand on.)

All this happens well before the Moon begins grazing the atmosphere. That's when things start vapourizing.
 
  • #55
Well, my class was discussing impact objects and their effects on Earth. We kept moving up to bigger and bigger objects, and by the time class ended, my mind was spinning different scenarios. That's why I was curious.

Do you think the surface would be molten before the Moon would even get there? Would it be due to the volcanism and earthquakes? Wouldn't that raise the temperature on the planet as well?
 
  • #56
DaveC426913
Gold Member
19,099
2,615
Do you think the surface would be molten before the Moon would even get there?
Very much dependent on the scenario.

If it happened rapidly, it would probably impact before much could get molten.
If it happened slowly, Earth's crust would get rent asunder, releasing magma.
If it happened very slowly, Earth's surface might get nicely liquified like a chicken on a rotisserie.

Would it be due to the volcanism and earthquakes?
Yes, but even larger effects too. The actual distortion of the bodies into elongated ellipses would generate a huge amount of heat.

This is before the Moon separates into large chunks. I'm not sure if the Earth would get torn apart. I'm not sure if the Moon is big enough to do that.


You can read up om Roche Limits:
http://en.wikipedia.org/wiki/Roche_limit
There are examples that relate to Earth/Moon.

Wouldn't that raise the temperature on the planet as well?
That is an understatement.
 
  • #57
309
0
In a perceived Godless universe where rogue black holes, roge stars and even rogue planets are considered a reality, I don't see why such a scenario couldn't occur.
 
  • #58
DaveC426913
Gold Member
19,099
2,615
In a perceived Godless universe where rogue black holes, roge stars and even rogue planets are considered a reality, I don't see why such a scenario couldn't occur.
Okaaay... This is kind of stating the obvious.

Pretty sure no one was suggesting it could not happen.


However, do note that this scenario is not anywhere in a vast, vast universe; it is specifically Earth/Moon.

So, no rogue planets, no rogue stars and no rogue black holes.
 
Last edited:
  • #59
2
0
I just registered to reply on this even though i have nothing with physics. I googled 'moon hit earth' and found this post.

I had the same dream! It freaked me out as well. I only dreamed i was sitting at home, and when i looked outside i saw the moon, but it was HUGE and seemed to be really close. I got really scared and it freaked me out. Then suddenly i became a spectator in my dream, as floating in space. And then i saw the moon, hit the earth. I was so so scared, the earth got damaged for a huge part, but the bigger part was still in tact.
Well HOW ODD IS THIS? 2 people dreaming about the moon hitting the earth?
 
  • #60
782
3
akanura, we've explained at length in this thread that the Moon hitting the Earth is absurd. There's no reasonable way for the Moon to lose its orbital momentum and energy, except via exceptionally unlikely encounters with a heavy third body. Ain't happening tomorrow.
 
  • #61
2
0
I know but its weird, that 2 people have the same dream, and its not the most common dream. Its not as if we dream about flying or w/e Just scares me that someone dream the same odd **** that doesnt have a dream symbol, as me!
 
  • #62
Ryan_m_b
Staff Emeritus
Science Advisor
5,844
713
I just registered to reply on this even though i have nothing with physics. I googled 'moon hit earth' and found this post.

I had the same dream! It freaked me out as well. I only dreamed i was sitting at home, and when i looked outside i saw the moon, but it was HUGE and seemed to be really close. I got really scared and it freaked me out. Then suddenly i became a spectator in my dream, as floating in space. And then i saw the moon, hit the earth. I was so so scared, the earth got damaged for a huge part, but the bigger part was still in tact.
Well HOW ODD IS THIS? 2 people dreaming about the moon hitting the earth?
I know but its weird, that 2 people have the same dream, and its not the most common dream. Its not as if we dream about flying or w/e Just scares me that someone dream the same odd **** that doesnt have a dream symbol, as me!
It isn't odd at all, after all every year there are over two and a half trillion dreams! And an asteroid hitting the moon isn't even that weird a concept. Now let's stick with what the thread is actually about and not get dragged into any crazy speculation on dreams.
 
  • #63
It isn't odd at all, after all every year there are over two and a half trillion dreams! And an asteroid hitting the moon isn't even that weird a concept. Now let's stick with what the thread is actually about and not get dragged into any crazy speculation on dreams.
Here is my one comment about this dream and the moon knocked out of orbit by asteroid/planetoid concept...Could it be that somehow you and that other dreamer either read or heard about these works of young adult fiction by Susan Beth Pfeffer?
Life As We Knew It (pub. 2006), The Dead And The Gone (pub. 2008), and This World We Live In (pub. 2010) aka the Last Survivors series .
 
  • #64
Ryan_m_b
Staff Emeritus
Science Advisor
5,844
713
Here is my one comment about this dream and the moon knocked out of orbit by asteroid/planetoid concept...Could it be that somehow you and that other dreamer either read or heard about these works of young adult fiction by Susan Beth Pfeffer?
Life As We Knew It (pub. 2006), The Dead And The Gone (pub. 2008), and This World We Live In (pub. 2010) aka the Last Survivors series .
I didn't have a dream. I was responding to someone who claimed to have a dream about it. Whilst I've never heard of Pfeffer I don't doubt that some of her readers may have had a dream like that. The majority of people though are just dreaming of a fairly simple idea.
 
  • #65
1
0
I just registered to reply on this even though i have nothing with physics. I googled 'moon hit earth' and found this post.

I had the same dream! It freaked me out as well. I only dreamed i was sitting at home, and when i looked outside i saw the moon, but it was HUGE and seemed to be really close. I got really scared and it freaked me out. Then suddenly i became a spectator in my dream, as floating in space. And then i saw the moon, hit the earth. I was so so scared, the earth got damaged for a huge part, but the bigger part was still in tact.
Well HOW ODD IS THIS? 2 people dreaming about the moon hitting the earth?
That makes four of us now, I had the same dream too, several months ago. I was starting to wonder now that 2005 YU55 will be passing by, could it really happen? Good to see smarter people than myself able to explain why it could NOT happen.
 
  • #66
2
0
I had this dream last night. I googled "could the moon hit Earth" and found this page. I consider myself a person of science and would not normally believe in this scenario, however, it disturbs me that my subconcious mind would create this event even though I think it ridiculous. Then to find out that other people have had this dream is really bothersome. I know I have never seen any movie or media that would influence my dreams to create such an event. Is there any way that this COULD possibly happen?
 
  • #67
782
3
I had this dream last night. I googled "could the moon hit Earth" and found this page. I consider myself a person of science and would not normally believe in this scenario, however, it disturbs me that my subconcious mind would create this event even though I think it ridiculous. Then to find out that other people have had this dream is really bothersome. I know I have never seen any movie or media that would influence my dreams to create such an event. Is there any way that this COULD possibly happen?
Presuming you're not a troll and multi-posting just to annoy people, then - as this thread explains - the described event basically has a ZERO probability. There's no way something can hit the moon and cause it to fall into the Earth. Even if the Moon was totally shattered, that wouldn't cause it to fall to Earth.
 
  • #68
2
0
Presuming you're not a troll and multi-posting just to annoy people, then - as this thread explains - the described event basically has a ZERO probability. There's no way something can hit the moon and cause it to fall into the Earth. Even if the Moon was totally shattered, that wouldn't cause it to fall to Earth.
Thank you for your response. No, I'm not a troll and normally wouldnt take the time to post on forums, but as this dream was very vivid, disturbing, and since other people have had the same dream, I thought it would be worth sharing. I actually wrote it down and noted in on my FB page as follows:

My Nightmare

May-2-2011

I was standing outside; I don't remember where I was or who I was with, I only know that I was not alone. It seemed as though it should have been nighttime though it was very bright out. I remember that my gaze was transfixed on the sky and I felt an incredibly vivid sense of disbelief and the most horrifying feeling of sadness and anguish which Shakespeare himself couldn't possibly begin to describe.
I can recall -very clearly- looking into the sky at the moon, but it was approximately 50 times larger than normal. Basically, the massive silvery-yellow body had captured the entire area of my peripheral view. I could visibly make out detailed surface formations of the object which would normally have been unnoticeable to the naked eye as it appeared to slowly draw closer to the Earth.
My memory of the dream gets somewhat hazy at this point, but I do recall checking some form of news media to get updated information on the event. I specifically remember feeling concerned about the time until impact.
The realness of the dream was so intense that I'm still consumed by the indescribable emotions which pulsate through my soul upon its recollection. The fact that my subconscious mind would devise such an event, considering that to the best of my knowledge the laws of physics and thermodynamics render it impossible, has me most perplexed. What's even more troubling, is that upon my Googling the possibility of a "moon hitting Earth" scenario, I've discovered that many other people have had nearly the exact same dream...and that's just creepy!


Please note that nothing in my dream gave any indication that the moon was actually struck by another object. Then again, considering the size it was in my dream, I would assume I missed the cause of its new trajectory.
 
  • #69
Ryan_m_b
Staff Emeritus
Science Advisor
5,844
713
I don't see any need to keep this thread open; over 7 billion dreams happen every day. The fact that some of them are similar and involve an object in the sky and an object under their feet is nothing special.
 

Related Threads on Asteroid hits moon → moon hits Earth possible?

  • Last Post
Replies
1
Views
5K
  • Last Post
Replies
5
Views
3K
Replies
9
Views
2K
  • Last Post
Replies
1
Views
5K
Replies
20
Views
3K
Replies
2
Views
2K
Replies
4
Views
2K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
7
Views
3K
Top