A good read on the asteroid hit and how timing (as always) is everything.

30 Seconds May Have Made All the Difference for Dinosaurs

I guess 'god' isn't a dinosaur fan.

-------------------------------------------

According to an upcoming BBC documentary, location, location, location made all the difference for the dinosaurs when it came to a mass extinction event 66 million years ago. But the dinosaurs' loss was our gain, as this cataclysmic global die-off paved the way for the rise of mammals–and humans.

Researchers believe that if the 9-mile wide asteroid had made impact less than a minute before or after it did, it likely would have crashed into the much deeper Atlantic or Pacific oceans, and not in the Gulf of Mexico, where shallower waters resulted in a massive, dense cloud of vaporized sulfur (as much as 100 billion tons worth) that wiped out the dinosaurs. As professor Ben Garrod, a co-presenter of “The Day the Dinosaurs Died” special, told the BBC, “it wasn’t the size of the asteroid, the scale of blast, or even its global reach that made dinosaurs extinct–it was where the impact happened.”

The resulting massive cloud blocked out the sun, leading to a dramatic cooling period, or “global winter,” which lasted for more than a decade and saw temperatures drop below the freezing level. As Garrod told the NY Post, “As the lights went out, global temperatures plunged more than 50 degrees Fahrenheit within days.”

Researchers believe that if the 9-mile wide asteroid had made impact less than a minute before or after it did, it likely would have crashed into the much deeper Atlantic or Pacific oceans, and not in the Gulf of Mexico, where shallower waters resulted in a massive, dense cloud of vaporized sulfur (as much as 100 billion tons worth) that wiped out the dinosaurs. As professor Ben Garrod, a co-presenter of “The Day the Dinosaurs Died” special, told the BBC, “it wasn’t the size of the asteroid, the scale of blast, or even its global reach that made dinosaurs extinct–it was where the impact happened.”

The resulting massive cloud blocked out the sun, leading to a dramatic cooling period, or “global winter,” which lasted for more than a decade and saw temperatures drop below the freezing level. As Garrod told the NY Post, “As the lights went out, global temperatures plunged more than 50 degrees Fahrenheit within days.”

Artist recreation of the asteroid that wiped out the dinosaurs
Artist recreation of the asteroid that wiped out the dinosaurs. (Credit: iStockphoto.com)
With nearly all vegetation and most animal life dead within months or a few years thanks to an endless grey sky, those dinosaurs who didn’t die in the immediate aftermath of the asteroid (or thanks to the resulting tsunamis and molten debris that fell from the sky) would have starved to death as their food sources disappeared. In all, it’s estimated that three-quarters of all life on Earth was destroyed.

Working at the Chicxulub crater, 24 miles off Mexico’s Yucatan Peninsula, scientists drilled a half-mile deep into gypsum-rich rock to examine the remnants of the asteroid, which left behind a gaping, 111-mile-wide by 20-mile-deep hole. They estimate that the asteroid was 9 miles wide, tiny in comparison to Earth (according to The Times, that’s like a grain of sand hitting a bowling ball), and traveling at 40,000 mph.

Its impact, reports Yahoo, contained the energy of 10 billion atomic bombs, causing a tower of matter taller than the Himalayas (and topping 18,000 degrees Fahrenheit) to shoot into the sky. Nearly everything within 600 miles would have been destroyed instantly, and significant damage has been detected in sites more than 1,600 miles away from the crater.

But while the asteroid’s timing spelled doom for the dinos, it opened the door for humans. The disappearance of these fearsome predators allowed for other animals, including our own mammal ancestors to thrive. As Alice Roberts, a scientist and co-presenter of the BBC special told The Times, “As the clouds started to clear a tiny group of animals came out of hiding to inherit Earth. With the dinosaurs gone, suddenly the landscape was empty of competitors and ripe with possibilities.”

If we are all alone, it seems like an awful waste of space. Carl Sagan

If they're advanced enough to get to us, they'll already know where we are and who we are, no matter if we broadcast our existence or not!

For us to not send out radio waves and/or invite our presence to other life in the universe is like asking a baboon to not show the colors of its rear to the world for the sake of not identifying itself. In the end, it makes no difference. You can still tell its there.

I believe we are not alone, had company in the past, and have company now. I don’t think we need to be signaling.

Maybe. I have moved steadily away from there must be countless environments that can sustain life and our solar system is not unique to more of a wow we got luck view of the universe.
Much of what is now the leading theory about the Earth Moon system and how we formed makes me believe such systems are not the norm. Or even simply rare. Many of the exoplanets, exo solar systems we have found do not look like ours. Yes there is an obersavtion bias, we can not yet directly detect rocky planets our size around stars. And we can not even directly observe most stars. As far as older civilizations go, well the early universe would not have been a great place for life to start, if there was even enough heavy elements for life to use. So I would be surprised but not shocked if no other life was ever found in our local galactic cluster, but most likely shock and surprised if in the entire universe, future included, no other life arose.

PS as for the dinosaurs and the meteor killing then off, the meteor may have simply been the straw that broke the camel's back. Or another luck (unlucky?) coincidence.

quote:

I don't think we even have the capability to see planets beyond the Milky Way. How could we possibly know what relationship exists between the majority of planets and moons?

while we have no current means of detecting them directly, the way they are observed is through the disturbance they create from their gravitational attractions with their surroundings

Pluto was hypothesized because the orbit of Neptune didn't follow its predicted path and the perturbations in the orbit pointed to a large object of sufficient mass that would be able to cause the disparity - and they were pretty accurate in size and mass

the other ways that some planets around distant stars are 'observed' is to look at the spectra and the brightness - as a planet passes in front of the star, a small amount of light is blocked making a change in brightness detectable. After a few measurements of this, the apparent size can be determined by mathematics, as is the orbit (hence the distance away from the star)

I'm no scholar, far from it, but I have always wondered why people assume life requires liquid water, and relatively moderate temperatures, just because we do. If you believe that life develops over millions of years then it has to begin and evolve to live in the environment at hand, whatever that might be.

Life on earth is such a miniscule sample size, compared to the entire universe, it statistically means nothing.

Life DID start from another chemical base here, however it changed the environment to what we have now.

Literally poisoned itself to extinction with Oxygen.

quote:

Originally posted by Mars_Attacks:
Life DID start from another chemical base here, however it changed the environment to what we have now.

Literally poisoned itself to extinction with Oxygen.

You must be referring to stromatolites.

Yep. They caused the Oxygen Crisis and the great global cooling.

The Earth had to be teraformed for us to live here.

Three billion years of them paved the way for advanced life to start in the Cambrian explosion.

Flowering plants arrived AFTER mammals.

So in order for us to meet ET, they will have to be at least old as we are and not have destroyed themselves or met some catastrophic fate.

I don't know, but if they are advanced enough to know of our presence then they would be smart to avoid contact until we get our "stuff' together.

It doesn't matter if we intentionally signal them or not because inadvertently we already are due to radio waves we transmit for our own uses.

I wonder if some aliens somewhere are sitting around tonight using a translator and enjoying a "live" radio broadcast of The Shadow, The Lone Ranger, maybe even The Jack Benny Show.
It's possible IMO.

On a universal scale the entirety of human history is but a fleeting second on a single celestial body in a place so big with so many other such bodies we don't and can't yet even see or measure its boundaries and can barely comprehend what we do know..., despite our otherwise fairly astonishing progress in just the last few hundred years...

We will come and go, planets will still orbit suns, space will still be cold and quiet, whether we or even this planet exist at all. The universe itself is utterly ambivalent to all things human. Like a particle of dust on a bump on the ass of a tiny gnat in a swamp in the Amazon is to us, or a single molecule of salt is to the entirety of all Earth's oceans, that's us.

What we do with this opportunity is what's most important. Be something. Do something. Create something. But do enjoy it while it lasts. There may very well be nothing else but these scant >120 years for each and every one of us. I work/seek to make the most of it, and remain ever fascinated by our increasing knowledge in these areas.

Those Pluto photos were incredible, for instance, the time, distance, quality, and challenge.

quote:

Originally posted by flashguy:

quote:

Originally posted by Shaql:
The thing that makes me wonder what the percentages are, is the moon. According to everything I've seen, our moon is an exception. Lots of planets have moons but none that are the size of, nor have the influence of, ours.

Our moon appears to be an exception which allows many of the other items listed above (stable rotation, seasons, tidal action to create the first goo, etc...). Heck, even the creation of the moon may have been what gave us our metallic core.

Isaac Asimov wrote several articles about that idea--he referred to the Earth-Moon system as a Double Planet. He pointed out a number of anomalies regarding our Moon. For example, the Sun has more gravitational impact on the Moon than the Earth does. For another, the orbit of the Moon around the Sun is never concave--it is always curved toward the Sun; the curvature fluctuates, but never turns outward. Our Moon is 1/4 the diameter of its primary (Earth) and it's surface gravity is 1/6--no other moon even comes close to those values.

The impact of the Moon on the Earth is enormous. It stabilizes our axis of rotation, causes (at least partly) our tides, and is the most luminous body in our night sky. It has been postulated that without the Moon, life might have never developed here. (God works in mysterious ways.)

flashguy

You missed out one VERY important fact about the moon. Its diameter and distance means that it EXACTLY obscures the sun at full eclipse. How much of an off-chance is that?

That, Friend, is nothing less than spooky in the extreme.

tac, NOT a proponent of Intelligent Design, but.................

quote:

Originally posted by JALLEN:I have been reading that a few hundred years ago, experts at the time assured their contemporaries that the earth was ~6,000 years old, and ~4,400 years since Adam, IIRC.

A few hundred years ago? Heck, there are people today who believe that. I stood on the rim of Hell's Canyon in Oregon a couple of years back, and listened to a couple of guys who had just turned up on their mega-Harleys. They looked down the gaping chasm, and blew their cheeks out, exclaiming that it 'sure was amazing that all this was done in just one day, six thousand years back....'.

Sure, people are entitled to believe in anything they want to, providing, IMO, that it doesn't cause any harm or distress to others. But it surely does seem strange to see what appeared to be two well-educated and prosperous young men with what, to me, seemed to be an outlandish world view.

tac

quote:

Originally posted by tacfoley:

quote:

Originally posted by flashguy:

quote:

Originally posted by Shaql:
The thing that makes me wonder what the percentages are, is the moon. According to everything I've seen, our moon is an exception. Lots of planets have moons but none that are the size of, nor have the influence of, ours.

Our moon appears to be an exception which allows many of the other items listed above (stable rotation, seasons, tidal action to create the first goo, etc...). Heck, even the creation of the moon may have been what gave us our metallic core.

Isaac Asimov wrote several articles about that idea--he referred to the Earth-Moon system as a Double Planet. He pointed out a number of anomalies regarding our Moon. For example, the Sun has more gravitational impact on the Moon than the Earth does. For another, the orbit of the Moon around the Sun is never concave--it is always curved toward the Sun; the curvature fluctuates, but never turns outward. Our Moon is 1/4 the diameter of its primary (Earth) and it's surface gravity is 1/6--no other moon even comes close to those values.

The impact of the Moon on the Earth is enormous. It stabilizes our axis of rotation, causes (at least partly) our tides, and is the most luminous body in our night sky. It has been postulated that without the Moon, life might have never developed here. (God works in mysterious ways.)

flashguy

You missed out one VERY important fact about the moon. Its diameter and distance means that it EXACTLY obscures the sun at full eclipse. How much of an off-chance is that?

That, Friend, is nothing less than spooky in the extreme.

tac, NOT a proponent of Intelligent Design, but.................

Except that the moon was at one time gigantic in the night sky; it is very slowly inching away from earth; that it is just the right size to cover the Sun an eclipse now is just a coincidence in the passage of time.

Of course, we'll likely be long gone before we can tell the difference, but some day millions (about 500 million or so) of years in the future, there won't be any more full eclipses of the sun by the moon.

http://www.bbc.com/news/science-environment-12311119

quote:

Originally posted by gearhounds:

quote:

Originally posted by tacfoley:

quote:

Originally posted by flashguy:

quote:

Originally posted by Shaql:
The thing that makes me wonder what the percentages are, is the moon. According to everything I've seen, our moon is an exception. Lots of planets have moons but none that are the size of, nor have the influence of, ours.

Our moon appears to be an exception which allows many of the other items listed above (stable rotation, seasons, tidal action to create the first goo, etc...). Heck, even the creation of the moon may have been what gave us our metallic core.

Isaac Asimov wrote several articles about that idea--he referred to the Earth-Moon system as a Double Planet. He pointed out a number of anomalies regarding our Moon. For example, the Sun has more gravitational impact on the Moon than the Earth does. For another, the orbit of the Moon around the Sun is never concave--it is always curved toward the Sun; the curvature fluctuates, but never turns outward. Our Moon is 1/4 the diameter of its primary (Earth) and it's surface gravity is 1/6--no other moon even comes close to those values.

The impact of the Moon on the Earth is enormous. It stabilizes our axis of rotation, causes (at least partly) our tides, and is the most luminous body in our night sky. It has been postulated that without the Moon, life might have never developed here. (God works in mysterious ways.)

flashguy

You missed out one VERY important fact about the moon. Its diameter and distance means that it EXACTLY obscures the sun at full eclipse. How much of an off-chance is that?

That, Friend, is nothing less than spooky in the extreme.

tac, NOT a proponent of Intelligent Design, but.................

Except that the moon was at one time gigantic in the night sky; it is very slowly inching away from earth; that it is just the right size to cover the Sun an eclipse now is just a coincidence in the passage of time.

Of course, we'll likely be long gone before we can tell the difference, but some day millions (about 500 million or so) of years in the future, there won't be any more full eclipses of the sun by the moon.

http://www.bbc.com/news/science-environment-12311119

Not to mention it has an elliptical orbit, so there are plenty of times where the size of the Moon doesn't match exactly the diameter of the sun.

quote:

Originally posted by cparktd:
I'm no scholar, far from it, but I have always wondered why people assume life requires liquid water, and relatively moderate temperatures, just because we do. If you believe that life develops over millions of years then it has to begin and evolve to live in the environment at hand, whatever that might be.

Life on earth is such a miniscule sample size, compared to the entire universe, it statistically means nothing.

If I remember correctly, the basic thinking is that an oxidation-reduction chemistry is what is needed as well as a medium that has a gas-liquid-solid temperature range to act as a thermal regulating mechanism. Water is kind of unique in this respect and has the additional aspect that the solid form floats on the liquid form.

Methane is another possible medium to provide a similar mechanism but it has a narrower temperature range and is not as good an oxidation-reduction mechanism.

It has been a while since I was interested in this kind of stuff, so my memory may be a bit off.

Ken

quote:

Originally posted by RHINOWSO:

quote:

Originally posted by gearhounds:

quote:

Originally posted by tacfoley:

quote:

Originally posted by flashguy:

quote:

Originally posted by Shaql:
The thing that makes me wonder what the percentages are, is the moon. According to everything I've seen, our moon is an exception. Lots of planets have moons but none that are the size of, nor have the influence of, ours.

Our moon appears to be an exception which allows many of the other items listed above (stable rotation, seasons, tidal action to create the first goo, etc...). Heck, even the creation of the moon may have been what gave us our metallic core.

Isaac Asimov wrote several articles about that idea--he referred to the Earth-Moon system as a Double Planet. He pointed out a number of anomalies regarding our Moon. For example, the Sun has more gravitational impact on the Moon than the Earth does. For another, the orbit of the Moon around the Sun is never concave--it is always curved toward the Sun; the curvature fluctuates, but never turns outward. Our Moon is 1/4 the diameter of its primary (Earth) and it's surface gravity is 1/6--no other moon even comes close to those values.

The impact of the Moon on the Earth is enormous. It stabilizes our axis of rotation, causes (at least partly) our tides, and is the most luminous body in our night sky. It has been postulated that without the Moon, life might have never developed here. (God works in mysterious ways.)

flashguy

You missed out one VERY important fact about the moon. Its diameter and distance means that it EXACTLY obscures the sun at full eclipse. How much of an off-chance is that?

That, Friend, is nothing less than spooky in the extreme.

tac, NOT a proponent of Intelligent Design, but.................

Except that the moon was at one time gigantic in the night sky; it is very slowly inching away from earth; that it is just the right size to cover the Sun an eclipse now is just a coincidence in the passage of time.

Of course, we'll likely be long gone before we can tell the difference, but some day millions (about 500 million or so) of years in the future, there won't be any more full eclipses of the sun by the moon.

http://www.bbc.com/news/science-environment-12311119

Not to mention it has an elliptical orbit, so there are plenty of times where the size of the Moon doesn't match exactly the diameter of the sun.

Right now, the apparent diameter of the Moon suits me just fine.

tac

quote:

Originally posted by tacfoley:You missed out one VERY important fact about the moon. Its diameter and distance means that it EXACTLY obscures the sun at full eclipse. How much of an off-chance is that?

I actually had to look this one up to be sure. Most eclipses are mismatched one way or the other for the reasons Rhino stated.