Why does Earth have so few impact craters?

[Garry Routh]

Astronomy is one of my pastimes. Looking at the moon, Mercury, and Mars, one sees a great deal of impact craters. Given, the Earth has an atmostphere that burns up the smaller meteors. Looking at the moon and the size of the average crater, the atmosphere would have done little to stop the impact.

Within the circle of the moon's orbit, on average we have asteroids big enough to destroy life as we know it on Earth come that close about 1.5 times a month.... apparently over centuries. Most nights meteors run at about one an hour for watching.

Why do we have so few craters? The universe is the most hostile environment possible for mankind. Soaking radiation and excessive extremes of temperature. Yet here we are cozy in our homes with a history of the masses never thinking about it.

Garry Routh

[Sam Ayyam]

Weather.

We have weather, oceans, rivers, lakes. Over geological timescales, all but the most pronounced impact features have been erased by time. It was only recently that the crater of what scientists believe was the dinosaur-killer was found near Yucatan, and more than half of it is under water.

Bodies like the Moon, Mercury, Mars, &c. have no appreciable mechanism for erosion, so their craters, some billions of years old, are preserved for posterity.

[Garry Routh]

I understand about the weather aspects. Count the number of impacts on the moon, it is smaller than we are and not quite the target. The average impact on the moon is almost as large as the largest on earth. I have visited two on earth. I also find it curious as to why the moon is not hit more than it is now. With as many meteors as we see in a twenty-four hour period, seems like we could occasioanlly witness new impacts on the moon too.

Garry Routh

[Islanders_for_the_cup_04]

Those impact craters you see on the moon accumulated over BILLIONS of years!!!!

Given the timespan, even ten thousand is miniscule. You also have to account for the fact that our atmosphere burns up a lot of these meteors before they hit the ground. A meteor that weighs 100 pounds is enough to cause massive devastation.

[gaiacomm]

Astronomy is one of my pastimes. Looking at the moon, Mercury, and Mars, one sees a great deal of impact craters. Given, the Earth has an atmostphere that burns up the smaller meteors. Looking at the moon and the size of the average crater, the atmosphere would have done little to stop the impact.

Within the circle of the moon's orbit, on average we have asteroids big enough to destroy life as we know it on Earth come that close about 1.5 times a month.... apparently over centuries. Most nights meteors run at about one an hour for watching.

Why do we have so few craters? The universe is the most hostile environment possible for mankind. Soaking radiation and excessive extremes of temperature. Yet here we are cozy in our homes with a history of the masses never thinking about it.

Garry Routh


Yes, that is true. Dust in the Wind of the Universe!

[hoot]

Age and lack of erosion factors on the moon. I think most[90%+] of the impact craters were made 4+ billion years ago on both the moon and on earth. Those on earth have been erased by erosion. Interesting that the largest on the moon {125 miles in diameter}is smaller than that one in the Gulf of Mexico{140 miles in diameter}, but we may have a weaker crust rock that will produce larger impact craters because of the underlying liquid mantle. This also has to have been a factor in produceing the Mares[seas] on the moon from leaking molten material after severe early impacts. Interesting, the very few very sharp impacts in these mares areas.

[Ingrid]

No one has addressed biggest difference between Earth and Moon: atmosphere! Friction caused by atmosphere causes great heat, which disperses many objects that fall to surface of Earth. Moon does not have this protection. Atmosphere is like protective coating in this manner. Big enough object could still make giant impact crater, of course, but many objects become size of small boulder by time of landing.

This, and other explanations offered here.

Oh, one more thing: Large amount of Earth's surface is water.

[Gerry]

No one has addressed biggest difference between Earth and Moon: atmosphere! Friction caused by atmosphere causes great heat, which disperses many objects that fall to surface of Earth. Moon does not have this protection. Atmosphere is like protective coating in this manner. Big enough object could still make giant impact crater, of course, but many objects become size of small boulder by time of landing.

This, and other explanations offered here.

Oh, one more thing: Large amount of Earth's surface is water.



Bevisa att dessa fane att du riktig

[Ingrid]

Bevisa att dessa fane att du riktig

Bevisa så pass en cirkel är inte en smula fyrkant :)

[April15]

You two,
I know you are not exchanging pleasantrys.

[Ingrid]

You two,
I know you are not exchanging pleasantrys.

I have said nothing unkind. Also, I will not do so!

[Gerry]

The holy virgin "Ingrid" cannot answer the Swedish sentence I wrote, but asks me to put a circle into a square. Good going FBWC. LOL

[Gerry]

I have said nothing unkind. Also, I will not do so!

No, as the holy virgin he has a reputation to uphold. LOL

[April15]

Translate please.

[Gerry]

About this post

I can readily see that this does NOT belong in Current Affairs. Craters in the Earth have absolutely NOTHIN, ZIP, NADA to do with anything current, or future. Nope :-)

Someone is cracked. The lunatics run the asylum.

[Gerry]

Translate please.

Translate WHAT?

[April15]

Nurse Ratchet!

[Ingrid]

Translate please.

Literal translation of "Bevisa att dessa fane att du riktig" is

Bevisa - Prove
att - that
dessa - these
fane - veneer
att - that
du - you
riktig - right

"Prove that these veneer that you right."

Is nonsense. Possibly, question should have had word "teoretisera - theories," or "förklaringarna - explanations," or even "sakerna - things." I do not know answer to this.

So I responded "Bevisa så pass en cirkel är inte en smula fyrkant."

Bevisa - prove
så pass - that
en cirkel - a circle
är inte - is not
en smula - a bit
fyrkant - square

"Prove that a circle is not a bit square."

This was joke.

[Mike]

About this post

I can readily see that this does NOT belong in Current Affairs. Craters in the Earth have absolutely NOTHIN, ZIP, NADA to do with anything current, or future. Nope :-)

Someone is cracked. The lunatics run the asylum.Gerry, pull your head out from wherever you have it inserted. This thread was posted TO THIS FORUM. It wasn't moved here.by anyone as far as I know.

[April15]

Ingrid,
Thank you. I was hopeing for gerry to translate but that is OK.

[Gerry]

Literal translation of "Bevisa att dessa fane att du riktig" is

Bevisa - Prove
att - that
dessa - these
fane - veneer
att - that
du - you
riktig - right

"Prove that these veneer that you right."

Is nonsense. Possibly, question should have had word "teoretisera - theories," or "förklaringarna - explanations," or even "sakerna - things." I do not know answer to this.

So I responded "Bevisa så pass en cirkel är inte en smula fyrkant."

Bevisa - prove
så pass - that
en cirkel - a circle
är inte - is not
en smula - a bit
fyrkant - square

"Prove that a circle is not a bit square."

This was joke.

So much for his knowledge of Swedish. What it says is "Prove to this fan that you are right"

Yikes, keeping up the faking while he is drowning with his dictionary.

[Gerry]

Gerry, pull your head out from wherever you have it inserted. This thread was posted TO THIS FORUM. It wasn't moved here.by anyone as far as I know.

I am glad you added "as far as I know" Because you DON'T know. It was posted on the current affairs and moved here.

[Ingrid]

Swedish word for "fan" is "solfjäder."

"Prove to this fan that you are right" would be "Bevisa till att dessa solfjäder att du riktig."

Swedish is not Dutch.

[Gerry]

Swedish word for "fan" is "solfjäder."

"Prove to this fan that you are right" would be "Bevisa till att dessa solfjäder att du riktig."

Swedish is not Dutch.



wrong fan. Check different dictionary, jerk