Did Clay Trigger 1st Life on Earth?
The Daily Flash -Eco, Space, Tech (9/28)

"Asteroid Impacts are the Biggest Threat to Advanced Life in the Milky Way" -Stephen Hawking (The Weekend Feature)


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Stephen Hawking believes that one of the major factors in the possible scarcity of intelligent life in our galaxy is the high probability of an asteroid or comet colliding with inhabited planets. We have observed, Hawking points out in Life in the Universe, the collision of a comet, Schumacher-Levi, with Jupiter (below), which produced a series of enormous fireballs, plumes many thousands of kilometers high, hot "bubbles" of gas in the atmosphere, and large dark "scars" on the atmosphere which had lifetimes on the order of weeks.

It is thought the collision of a rather smaller body with the Earth, about 70 million years ago, was responsible for the extinction of the dinosaurs. A few small early mammals survived, but anything as large as a human, would have almost certainly been wiped out.

Through Earth's history such collisions occur, on the average every one million year. If this figure is correct, it would mean that intelligent life on Earth has developed only because of the lucky chance that there have been no major collisions in the last 70 million years. Other planets in the galaxy, Hawking believes, on which life has developed, may not have had a long enough collision free period to evolve intelligent beings.

Sl9calar“The threat of the Earth being hit by an asteroid is increasingly being accepted as the single greatest natural disaster hazard faced by humanity,” according to Nick Bailey of the University of Southampton's School of Engineering Sciences team, who has developed a threat identifying program.[ Image: Comet Shoemaker-Levy 9 collision with Jupiter]

The team used raw data from multiple impact simulations to rank each country based on the number of times and how severely they would be affected by each impact. The software, called NEOimpactor (from NASA's "NEO" or Near Earth Object program), has been specifically developed for measuring the impact of 'small' asteroids under one kilometer in diameter.

Early results indicate that in terms of population lost, China, Indonesia, India, Japan and the United States face the greatest overall threat; while the United States, China, Sweden, Canada and Japan face the most severe economic effects due to the infrastructure destroyed.

The top ten countries most at risk are China, Indonesia, India, Japan, the United States, the Philippines, Italy, the United Kingdom, Brazil and Nigeria.

Astrofisico_Stephen_Hawking“The consequences for human populations and infrastructure as a result of an impact are enormous,” says Bailey. “Nearly one hundred years ago a remote region near the Tunguska River witnessed the largest asteroid impact event in living memory when a relatively small object (approximately 50 meters in diameter) exploded in mid-air. While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25. Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat.”

What would happen to the human species and life on Earth in general if an asteroid the size of the one that created the famous K/T Event of 65 million years ago at the end of the Mesozoic Era that resulted in the extinction of the dinosaurs impacted our planet.

As Stephen Hawking says, the general consensus is that any comet or asteroid greater than 20 kilometers in diameter that strikes the Earth will result in the complete annihilation of complex life - animals and higher plants. (The asteroid Vesta, for example, one of the destinations of the Dawn Mission, is the size of Arizona).

How many times in our galaxy alone has life finally evolved to the equivalent of our planets and animals on some far distant planet, only to be utterly destroyed by an impact? Galactic history suggests it might be a common occurrence.

The first this to understand about the KT event is that is was absolutely enormous: an asteroid (or comet) six to 10 miles in diameter streaked through the Earth's atmosphere at 25,000 miles an hour and struck the Yucatan region of Mexico with the force of 100 megatons -the equivalent of one Hiroshima bomb for every person alive on Earth today. Not a pretty scenario!

Recent calculations show that our planet would go into another "Snowball Earth" event like the one that occurred 600 million years ago, when it is believed the oceans froze over (although some scientists dispute this hypothesis -see link below).

While microbial bacteria might readily survive such calamitous impacts, our new understanding from the record of the Earth's mass extinctions clearly shows that plants and animals are very susceptible to extinction in the wake of an impact.

Impact rates depend on how many comets and asteroids exist in a particular planetary system. In general there is one major impact every million years -a mere blink of the eye in geological time. It also depends on how often those objects are perturbed from safe orbits that parallel the Earth's orbit to new, Earth-crossing orbits that might, sooner or later, result in a catastrophic K/T or Permian-type mass extinction.

VredefortThe asteroid that hit Vredefort located in the Free State Province of South Africa is one of the largest to ever impact Earth, estimated at over 10 km (6 miles) wide, although it is believed by many that the original size of the impact structure could have been 250 km in diameter, or possibly larger(though the Wilkes Land crater in Antarctica, if confirmed to have been the result of an impact event, is even larger at 500 kilometers across). The town of Vredefort is situated in the crater (image). 

Dating back 2,023 million years, it is the oldest astrobleme found on earth so far, with a radius of 190km, it is also the most deeply eroded. Vredefort Dome Vredefort bears witness to the world’s greatest known single energy release event, which caused devastating global change, including, according to many scientists, major evolutionary changes. 

What has kept the Earth "safe" at least the past 65 million years, other than blind luck is the massive gravitational field of Jupiter, our cosmic guardian, with its stable circular orbit far from the sun, which assures a low number of impacts resulting in mass extinctions by sweeping up and scatters away most of the dangerous Earth-orbit-crossing comets and asteroids

Posted by Casey Kazan with Rebecca Sato

Note: This post was adapted from a news release issued by University of Southampton.

Source: http://www.rationalvedanta.net/node/131

Related Galaxy Posts:

The Dawn Mission -NASA's Journey to the Beginning of the Solar System

The End of the World -A Video (the most terrifying short film ever!)

Past as Prelude -Asteroids & the Origin of LIfe (Includes "Impact Map of the World")

A Future KT Impact Event -Would the Human Species Survive

Dr Strangelove Two? -Cambridge Astrophysicts gives Earthlings a 50/50 Chance of Survival by End of Century
 

Comments

Just looking at Steven Hawking makes me think about the revelations he made on how the human species should move to another planet if not face alien invasion.

This article is terrible, just like every other article I've ever read on this website. The science is wrong and misleading, and the writing is horrid.

Great and nice article. The impact events are typical in this zone of the galaxy and earth has suffered quite few main impacts. Thanks for sharing.

Thanks for the article. Its a funny thing, the randomness of the universe. A big asteroid could just come and have its way with us (unless of course Bruce Willis has something to say about it :) )
Its an interesting point about other potential civilizations wiped out, whereas we have had the sheer dumb luck to have survived.

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Asteroid impacts can be caused by stray rubble from the Asteroid Belt and the rocky snowballs that travel in highly elliptical orbits in the comet cloud. There are many fewer large bits of debris than small bits, so the interval between large impacts is much longer than the interval between small impacts.

This is the ultimate blog for anyone who wants to know about this subject. Thanks for sharing all these valuable infos.The title of your page caught my eye. You definitely have an unique way of writing with your thoughts. I just liked the article. It was Very refreshing post with attractive thoughts.It was wonderful to read your blog. The thoughts are very well arranged and it was refreshing to read.

The greatest evolutionary leaps are always post-extinction. It seems more likely that these mass extinctions have sped up evolution rather than to hinder it.I was able to get the facts that I was searching for. I would like to thank you for the initiatives you have made in writing this article.

W.Stephen Hawking is a great scientist and astronomer in the world.
He want to discover a new method on earth.Earth in general if an asteroid the size of the one that created the famous K/T Event of 65 million years ago at the end of the Mesozoic Era that resulted in the extinction of the dinosaurs impacted our planet.

Redis-benchmark was also improved, and now you can specify the exact command to benchmark, that is an awesome change. You can see an example run of the new redis-benchmark in the paragraph related to variadic commands.

Jeff Younger, I have to note that the most important metrics mentioned in that report are not available because the security situation etc doesn't let them be collected.

There are many fewer large bits of debris than small bits, so the interval between large impacts is much longer than the interval between small impacts.

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This content is dreadful, just like every other content I've ever study on this web page. The technology is incorrect and inaccurate, and the composing is dreadful.

Provide us with a record of all the public organizations that are actually doing something other then awaiting the unavoidable and allows put our cash and back to the rim of lifestyle .

have not watched the previous races because of my busy schedules but I am really excited to watch the event this October. I believe in your team and will support you all way! You're team is amazing.

It is obvious the countries with the large population will definitely the once which suffer most. But other forces also need to be considered. Electric universe anyone....

Though asteroid collisions are an obstacle to developed intelligent life but I think any intelligent civilization prepare itself in advance for any such threat. I do believe our governments had also considered some measures against this threat.

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