Originally posted by whodey
Has anyone heard rumors of a giant comet due to hit earth in September this year? Are there any comet due to come close to earth during this time?

Yes, Whodey, a giant comet the size of Betelgeuse is going to impact the Earth just before sunrise on September 18 in northeastern Wyoming. We're all doomed.

Originally posted by googlefudge

Its the smaller hard to see stuff, that could still cause a massive tsunami, or ...........
.

What did you think of that tsunami scare story about one
of the Canaries blowing up and drenching Western Europe?

Hollywood stuff or just a really remote possibility?

Originally posted by wolfgang59
What did you think of that tsunami scare story about one
of the Canaries blowing up and drenching Western Europe?

Hollywood stuff or just a really remote possibility?

AFAICT something which once was thought to be a one-in-a-gazillion possibility, but later research has revealed to be not even that. It now seems more likely that there will be a series of smaller tremors, each too small to trigger a tsunami.

Although, as I heard it, the wave would've gone the other way, towards the Eastern USA. Which makes more sense, because to get there it would only have to cross open ocean, while to get to Western Europe it'd have to bend all the way around the Iberian peninsula. Possible, but likely to absorb rather more energy. (In any case, if it went that way, northwest Africa would be the first to be hit.)

Originally posted by twhitehead
Rubble, is really small bits.

What size pieces do you estimate would cause a problem ie not burn up before exploding catastrophically or hitting the ground?

A metre is big enough to cause serious trouble There'd be many of them. Extinction it wouldn't be, certainly not immediately, but there'd be a lot of pain.

Anyway, don't land a bomb on it, land a rocket engine on it and push it away. It only takes a little shove over several days to make the difference between a direct hit and a very near miss.

(Also, "near Earth object" doesn't mean what it sounds like. The criterium is rather larger than what Hollywood and the Daily Mirror want you to believe. AIUI the official meaning is "passes nearer than the moon". Astronomically that is close by, but for target practice that's quite a margin...)

Originally posted by Soothfast
Yes, Whodey, a giant comet the size of Betelgeuse is going to impact the Earth just before sunrise on September 18 in northeastern Wyoming. We're all doomed.

The real question is: why is someone who claims to be a Christian giving credence to this new-age wooo-hooo story?

Originally posted by whodey
By the time people realized what was happening they would all be in their bunkers and disappear.

As for doing something about it, could they land rockets on the comet and then strap them on and then ignite the rockets to change their tragectory?

NASA has already proven then can land on them.

Actually, it wasn't NASA landing on a comet, it was the ESA, the result of a 10 year long journey to match speeds with it and just yesterday the lander woke up after being in the dark literally, for 7 months, now batteries are recharged and it is going back to work doing science.

http://www.esa.int/Our_Activities/Space_Science/Rosetta

Originally posted by wolfgang59
What did you think of that tsunami scare story about one
of the Canaries blowing up and drenching Western Europe?

Hollywood stuff or just a really remote possibility?

Well the direction of the resulting tsunami would drench eastern USA, not much would
actually head our way. [fortunately]

It's totally possible, it depends if, and how, the side of one of the islands collapses.

We have evidence of massive tsunamis being created by landslides in the past.
There was a massive tsunami that drenched the UK caused by an undersea landslide
off the continental shelf near Norway. [you can see the remains of that, and other landslides
in sonar maps of the ocean floor].

Hawaii exploding and collapsing has been blamed for massive prehistoric tsunamis that
drenched the pacific.


I believe that the latest thinking is that the likelihood of a massive tsunami from the canaries
is less likely than first thought. But there isn't enough certainty either way to be definitive.
Unless anyone has heard more up-to-date info.

Originally posted by twhitehead
Rubble, is really small bits.

What size pieces do you estimate would cause a problem ie not burn up before exploding catastrophically or hitting the ground?

If the rubble hits the Earth it doesn't matter if it all burns up in the atmosphere.

You have done nothing to reduce it's mass or velocity.

All you have done is deliver 100% of that biblically huge amount of energy to the atmosphere.

Raising half the planet to gas mark 6 and setting ever plant and animal in that area on fire is
going to be just as devastating if not more so than blowing a big hole in the ground.

Originally posted by googlefudge
If the rubble hits the Earth it doesn't matter if it all burns up in the atmosphere.

You have done nothing to reduce it's mass or velocity.

All you have done is deliver 100% of that biblically huge amount of energy to the atmosphere.

Raising half the planet to gas mark 6 and setting ever plant and animal in that area on fire is
going to be just as devastating if not more so than blowing a big hole in the ground.

Exactly! And that is the massive conceptual error in all the block-buster disaster movies which show the threat of an asteroid/comment impact magically going away when they nuke it!
I seen such a movie that showed them nuking an asteroid and then someone commenting vaguely alone the lines of "all the asteroid fragments are harmlessly burning up in the atmosphere"; -what about the massive ROASTING we get when they so-called "harmlessly" burn up in the atmosphere!!!?

Originally posted by sonhouse
I suspect if an asteroid was discovered it would be hit with a dozen nukes, hydrogen bombs of 10 megatons, all set to go off at the same time but scattered over the surface with some of them being bunker busters that can penetrate a few thousand feet before detonation. The sum total of 120 megatons going off I would think alter the orbital course enough so ...[text shortened]... he one percent left would still do significant damage but it would not be a civilization buster.

The Orion project involved a ~thousand ton space craft being propelled by multi-kiloton
nuclear blasts every few seconds, using hundreds to make it to orbit. [so ~megaton energies
required for 7.5km/s delta V]

A 1 km rocky asteroid weighs in at around the ~10 million trillion ton mark.

To achieve a similar effect on a 1km asteroid you need ~10 thousand trillion times more
energy than you need for the thousand ton space craft [which was optimally designed to
be thrusted by nuclear detonations].

~100 Mt TNT would give a deltaV [in this estimation] of the order of 0.00001 micro meters per second.

Now actual thrust will be higher than this as a portion of the mass of the asteroid will vaporise
giving off a thrust. [we are probably still in the mm per second or less]

But that thrust is still very small.

Which is fine if it's a LONG way out.

It's terrible if it's close.

Just hitting it with nukes is pretty much just going to turn it into radioactive rubble that will still
hit, and probably do more damage than it was going to before as it will dump more energy into
the atmosphere. And make it much harder to do anything else to deflect it.

Originally posted by humy
Exactly! And that is the massive conceptual error in all the block-buster disaster movies which show the threat of an asteroid/comment impact manically going away when they nuke it!
I seen such a movie that showed them nuking an asteroid and then a news presenter said something vaguely alone the lines of "all the asteroid fragments are harmlessly burning up in ...[text shortened]... about the massive ROASTING we get when they so-called "harmlessly" burn up in the atmosphere!!!?

Or, when we blow up the huge alien space ship with "one third the mass of the moon"
or "the Death Star" and bit's start raining down.

Endor's totally trashed by that Death Star explosion, the rebels just leave before all
the cute cuddly bears get wiped out.

Originally posted by googlefudge
All you have done is deliver 100% of that biblically huge amount of energy to the atmosphere.

How 'biblically huge' exactly? according to Wikipedia, the Chelyabinsk meteor, released the energy equivalent of 500 kilotons of TNT.
The only reason it caused serious damage - consisting of mostly broken windows, is because it exploded. Had it been composed of smaller pieces, there would have been practically no significant side effects at ground level.
https://en.wikipedia.org/wiki/Chelyabinsk_meteor

So the meteorite you are envisioning would be how much bigger? (Chelybinsk meteor was approximately 20m diameter)

Raising half the planet to gas mark 6 and setting ever plant and animal in that area on fire is
going to be just as devastating if not more so than blowing a big hole in the ground.
Please show at least back of hand calculation to justify that claim.

Originally posted by googlefudge
The Orion project involved a ~thousand ton space craft being propelled by multi-kiloton
nuclear blasts every few seconds,

With most notably, the blasts being external to the craft. Had they been contained, the thrust would be far greater.

Originally posted by googlefudge
The Orion project involved a ~thousand ton space craft being propelled by multi-kiloton
nuclear blasts every few seconds, using hundreds to make it to orbit. [so ~megaton energies
required for 7.5km/s delta V]

A 1 km rocky asteroid weighs in at around the ~10 million trillion ton mark.

To achieve a similar effect on a 1km asteroid you need ~10 ...[text shortened]... mp more energy into
the atmosphere. And make it much harder to do anything else to deflect it.

I used 3 grams/cm^3 for the mass, and came up with about 500 million tons for a 1 Km diameter rocky asteroid. I thought millions of trillions of tons was a bit off🙂 Take a look at an aircraft carrier, 100,000 tons and it is about 1200 feet long, about 360 meters, or .36 km. You couldn't fit more than ten or twenty of them inside a 1 km asteroid. I think your numbers are a bit off.

Originally posted by googlefudge
Or, when we blow up the huge alien space ship with "one third the mass of the moon"
or "the Death Star" and bit's start raining down.

Endor's totally trashed by that Death Star explosion, the rebels just leave before all
the cute cuddly bears get wiped out.

Oh yes, I remember the evolutionary absurd cute cuddly bears with their strangely poorly evolved body form for walking or running despite the fact they seemed to do a lot of both, and with the their silly sounding childish noises they make for communication that strangely doesn't sound like it actually consists of any words, and their heroic fight against the "dark side" despite their apparently severe natural physical handicap of having a body form that looks ill-suited to do anything very physical let alone deadly fighting.

What a totally ridiculous script.