# Comet Passing by Earth: Effects & Destruction

• mersecske
In summary, a huge meteor can cause to destroy the civilization. But let assume that a comet pass by the Earth. Can a comet cause such a big destruction without collision? A small comet with a non-solid rock core would almost certainly burn up in the upper atmosphere. A larger comet with a solid rock core could produce the same explosion as a similarly sized meteor.
mersecske
1)

A huge meteor can cause to destroy the civilization.
But let assume that a comet pass by the Earth.
Can a comet cause such a big destruction without collision?

2)

Let assume that a comet collide with the Moon.
This situation can cause such a big destruction on the Earth?

3)

And in the case of just small perturbation,
what kind of effects can be detected?
For example the length of he day can change?

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A typical comet might mass something like 1e15 kg. This is in the order of 1/100,000,000 the mass of the Moon. A near miss would have no measurable effect on the Earth.

A direct collision with the Moon would have less of an effect on the Moon's orbit than the variation it already exhibits due to its eccentricity, so again, the effects on Earth would be nil.

mersecske said:
1)

A huge meteor can cause to destroy the civilization.
But let assume that a comet pass by the Earth.
Can a comet cause such a big destruction without collision?

Depends on how big and how close. Close enough and tidal forces would cause earthquakes, but too close and the comet would break up, with unpredictable consequences. Smaller comets also leave a trail of debris behind them which can cause a meteor storm, though the meteors typically look spectacular without any effect on the ground.

2)Let assume that a comet collide with the Moon.
This situation can cause such a big destruction on the Earth?

Debris from the collision can either fall or collide with the Earth, with disastrous consequences, but the comet needs to be large.

3)And in the case of just small perturbation,what kind of effects can be detected?
For example the length of he day can change?

That's very unlikely as the angular momentum of the Earth is very large. Any perturbations will be very small, though probably measurable. If the 'comet' is hundreds of kilometers across - a dwarf planet - then its tidal interaction could cause perturbations of several minutes in a day.

mersecske said:
1)

A huge meteor can cause to destroy the civilization.
But let assume that a comet pass by the Earth.
Can a comet cause such a big destruction without collision?

It is my firm belief that the Tunguska event resulted because of an airburst of a meteor in the lower atmosphere of the earth.

A 10 meter meteor can cause an airburst comparable to the fatman nuclear device dropped on japan.

With the Tunguska event, the blast was directed downward at first and then traveled along the ground in an outward radius. The blast radius was 8 kilometers wide and scorched and laid flat trees. Windows were shattered in villages more than 200 miles from the blast.

The meteor completely burned up in the atmosphere. So it never impacted the Earth. But, it was extremely destructive, nonetheless, and would have been a horrific tragedy of historic proportions if the blast had occurred over a populated area.

I don't want to talk about meteors entering into the atmosphere.

mersecske said:
I don't want to talk about meteors entering into the atmosphere.

It happens many times every day.

What do you want to talk about? The question was pretty vagur.

If you are talking specifically about a comet, and you mean that it passes by the Earth but does not enter the atmosphere, then I don't know why you need an answer from us. Why would a comet traveling outside our atmosphere have any impact on humanity other than that it could possibly impact with a satellite?

Many comets have solid cores of rock in their nucleus. Others are a mixture of rock and ice. Smaller comets with non-solid rock interiors would almost certainly burn up in the upper atmosphere. A larger comet with a solid rock core could produce the same explosion as a similarly sized meteor.

mersecske said:
I don't want to talk about meteors entering into the atmosphere.

Janus' post #2 anwers any questions about near misses by comets.

mkarger said:
Why would a comet traveling outside our atmosphere have any impact on humanity other than that it could possibly impact with a satellite?

Many comets have solid cores of rock in their nucleus. Others are a mixture of rock and ice. Smaller comets with non-solid rock interiors would almost certainly burn up in the upper atmosphere. A larger comet with a solid rock core could produce the same explosion as a similarly sized meteor.

My question is theoretical for example a very big comet (bigger than real ones)
without entering the atmosphere can cause such effects.?

mersecske said:
My question is theoretical for example a very big comet (bigger than real ones)
without entering the atmosphere can cause such effects.?

Ah. Fiction. Well, all bets are off then, aren't they?

How big do you want this planetesimal to be? You'll have to start looking at some of the larger asteroids. Ceres is still 1/100th the mass of the Moon.

How close would you like it to come? Graze the atmo?

Last edited:

## 1. What is a comet?

A comet is a small icy body that orbits the sun. It is made up of dust, rock, and frozen gases such as water, carbon dioxide, methane, and ammonia. Comets are often referred to as "dirty snowballs" due to their composition.

## 2. How close can a comet pass by Earth?

The distance a comet can pass by Earth varies greatly. Some comets can come as close as a few thousand miles, while others can pass by at a distance of millions of miles. It depends on the trajectory of the comet and its speed.

## 3. What are the potential effects of a comet passing by Earth?

The effects of a comet passing by Earth can vary depending on the size and proximity of the comet. It can potentially cause meteor showers, changes in weather patterns, and disruptions to communication and navigation systems. In extreme cases, it could also cause mass extinction events.

## 4. Can a comet cause destruction on Earth?

It is possible for a comet to cause destruction on Earth, but it is not very likely. Most comets are small and burn up in the Earth's atmosphere before reaching the surface. However, a very large comet or one that comes in close proximity to Earth could potentially cause significant destruction.

## 5. What measures are in place to prevent a comet from colliding with Earth?

Currently, there are no specific measures in place to prevent a comet from colliding with Earth. However, scientists track and monitor comets using telescopes and satellites to predict their trajectories and potential impact. If a comet is deemed a threat, steps can be taken to deflect its path, such as using spacecraft to alter its trajectory or detonating a nuclear device near it to change its course.

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