As of today, there are currently 1453 known potentially hazardous asteroids that could impact Earth and cause a real planetary catastrophe. Given the new diverse “snow globe” model of our solar system in relation to asteroids, how may more don’t we know about? It only takes one. Of more pragmatic interest, this new paper suggests a diverse asteroid population stirred up in the ‘snow globe’ model was essential to bringing water to Earth.
From the Harvard-Smithsonian Center for Astrophysics Cambridge, MA –
Our solar system seems like a neat and orderly place, with small, rocky worlds near the Sun and big, gaseous worlds farther out, all eight planets following orbital paths unchanged since they formed.
However, the true history of the solar system is more riotous. Giant planets migrated in and out, tossing interplanetary flotsam and jetsam far and wide. New clues to this tumultuous past come from the asteroid belt.
“We found that the giant planets shook up the asteroids like flakes in a snow globe,” says lead author Francesca DeMeo, a Hubble postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics.
Millions of asteroids circle the Sun between the orbits of Mars and Jupiter, in a region known as the main asteroid belt. Traditionally, they were viewed as the pieces of a failed planet that was prevented from forming by the influence of Jupiter’s powerful gravity. Their compositions seemed to vary methodically from drier to wetter, due to the drop in temperature as you move away from the Sun.
That traditional view changed as astronomers recognized that the current residents of the main asteroid belt weren’t all there from the start. In the early history of our solar system the giant planets ran amok, migrating inward and outward substantially. Jupiter may have moved as close to the Sun as Mars is now. In the process, it swept the asteroid belt nearly clean, leaving only a tenth of one percent of its original population.
As the planets migrated, they stirred the contents of the solar system. Objects from as close to the Sun as Mercury, and as far out as Neptune, all collected in the main asteroid belt.
“The asteroid belt is a melting pot of objects arriving from diverse locations and backgrounds,” explains DeMeo.
Using data from the Sloan Digital Sky Survey, DeMeo and co-author Benoit Carry (Paris Observatory) examined the compositions of thousands of asteroids within the main belt. They found that the asteroid belt is more diverse than previously realized, especially when you look at the smaller asteroids.
This finding has interesting implications for the history of Earth. Astronomers have theorized that long-ago asteroid impacts delivered much of the water now filling Earth’s oceans. If true, the stirring provided by migrating planets may have been essential to bringing those asteroids.
This raises the question of whether an Earth-like exoplanet would also require a rain of asteroids to bring water and make it habitable. If so, then Earth-like worlds might be rarer than we thought.
The paper describing these findings appears in the January 30, 2014 issue of Nature.
Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.
I think Earth like planets are exceedingly rare. Its not just a matter of finding a rocky planet of roughly the right size that orbits a sun like ours and has a bit of water on it.
The Earth as we know it is the outcome of a series of massively improbable events:
We have a magnetic field – not so common even in our own solar system, but this protects us from the solar wind and protects our atmosphere from being stripped away. It also allows life to persist.
In order to have a magnetic field like ours also requires the coming together of a serious amount of factors. We have a molten core – which requires a certain amount of radioactivity and the core is iron rich so that when the Earth spins it generates a magnetic field. However, the Earth spins at a massive rate compared to most other planets and this should create such a wobble that the Earth should spin on a horizontal axis. Except that we have a moon of a certain size that acts as a dampener and keeps us vertical enough that we have seasons. Incidentally the Moon also acts as a “sweeper” for a lot of the asteroids that would otherwise have been caught in Earths gravity.
It seems to me that if you go looking for lumps of rock circling stars at the right distance you will find plenty of them. But if you are looking for Earth Like planets then that would be much harder.
I always understood that water came from the asteroids or at least meteorites, so I don’t know why this is something new.
To think of all the hate that Immanuel Velikovsky stirred up when he had the effrontery to suggest that Venus had been ejected from Jupiter and had wandered the Solar System as a comet, with near misses on Earth and Mars, before finally settling down in its current orbit!
Do you suppose that his reputation could finally be restored to him? He may be right or wrong, but so far there has been no conclusive evidence that he was wrong in any major part of his thesis – though possibly in parts that are not essential. Indeed, all recent discoveries tend to support his theories rather than the views of those who opposed and denigrated him so vigorously.
Nearly fell off the chair that “Nature” of all journals, actually prints a suggestion that Jupiter had at one time been as close to the Sun as Mars is now, and that the giant planets (including Saturn, Uranus and Neptune) “ran amok, migrating inward and outward substantially”. Where are Harlow Shapley, Cecilia Payne-Gaposchkin, Carl Sagan and Isaac Asimov now they are needed to defend the orthodox view – see, for example: http://www.unz.org/Pub/Reporter-1950mar14-00037 for Professor Payne-Gaposchkin’s article “Nonsense, Dr. Velikovsky!”
And one might wish to consider CAGW in the light of the last column of Professor Payne-Gaposchkin’s article!!
Goldie
“The Earth as we know it is the outcome of a series of massively improbable events:”
We have no way of knowing how improbable those events are in the larger galaxy / universe.
The only empirical evidence we have is our own solar system. Odds of 1 in 8, 1 in 9 or 1 in 10 depending on how you want to count planets. Odds of 1 in 10 do not count as massively improbable in my book.
@MattS – Kind of like a lottery winner saying the odds are not too bad, as he only bought 10 tickets and one of them won the jackpot.
I’ve yet to see a snow globe where the particles roughly align in a plane, unless you forget to shake the globe.
But why wouldn’t [the] planets have been closer. At one time our own moon was orbiting much closer to the Earth and the Earth was spinning much faster. All a consequence of a collision with Thea However as time passed and the spin has slowed, so the Moon has moved away from the Earth. I think that’s basic physics – conservation of momentum, but I’m not sure – I’m a Geologist precisely because I was no good at Maths.
[snip – off topic and out of bounds -mod]
RACookPE1978 says:
January 30, 2014 at 6:50 pm
===============
Gotcha, it’s all good.
My bad 🙁
Agree. Look up the work of Jinan Cao.
Gail Combs says: at 4:49 pm “Predators are generally smarter than prey….”
But what if what we call humanity is only a 4 on a predatory scale of 10?
There may be Kzin out there with a Payton Manning as QB.. How’s that for mixing cultural reference?
@Tom J –
As I understand it, the original composition of the Earth’s atmosphere, after the planet settled down at the end of its formative period, was roughly 80 percent nitrogen and 20 percent CO2 (ignoring the 1 percent or less of argon and other noble gases). Then, starting about 2 billion years ago, blue-green algae evolved and began the photosynthesis that eventually converted the CO2 to O2, a process that was essentially complete sometime before the Cambrian explosion of life on Earth, 600-700 million years ago. Clearly, there was no runaway heating on Earth during all that time, and there appears to have been at least one time where the Earth froze over entirely before the advent of the blue-green algae and the consequent redux of all that CO2.
Other commenters – anything to add (or correct) to this?
– Ed, Mr. Jones says:
January 30, 2014 at 6:25 pm
Why would Asteroids be more likely to be composed of, or with water than any other celestial body?
I don’t see an explanation or speculation thereto.-
Start with there is a lot hydrogen and Helium in the universe. The next most abundant element
is oxygen. So 2 hydrogen + oxygen is water. There also a lot H2O in the universe.
So asteroids in the main asteroid belt don’t have a lot water compared to other celestial bodies.
But also there lots asteroids in our solar system- or the asteroids in main asteroid belt are small fraction of all asteroid in our solar system.
The mass of main asteroid belt:
“The total mass of the Asteroid belt is estimated to be 3.0 to 3.6×10^21 kilograms, which is 4 percent of the Earth’s Moon.
Of that total mass, one third is accounted for by Ceres alone.”
http://www.sciencedaily.com/articles/a/asteroid_belt.htm
Ceres may have more water than all the asteroids in main asteroid belt. The amount of water
on Ceres is not known precisely, but estimate of it having more fresh water than Earth- and fresh water on Earth is very small percent of ocean water.
“This 100-km-thick mantle (23%–28% of Ceres by mass; 50% by volume) contains 200 million cubic kilometers of water, which is more than the amount of fresh water on the Earth”-
http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29
Earth’s oceans is about 1.3 trillion cubic km and fresh is about 10 million cubic km:
http://ga.water.usgs.gov/edu/earthhowmuch.html
And polar caps and glaciers hold most of fresh water.
So it’s very unlikely Ceres and the asteroids in main belt have as much water as Earth does.
Jupiter moon, Europa probably couple times more water than Earth.
http://io9.com/theres-more-water-on-jupiters-moon-europa-than-there-5913104
Mars is thought to have more tens trillion tonnes- or more than 10,000 cubic km of water.
Our Moon has somewhere around 10 billion tons- 10 cubic km of water. With perhaps millions of tonnes which might “commercially minable”. Moon used to be considered to not have “any water to speak of” which largely true. Moon is extremely dry, but water has be found in lunar poles-
making the Moon somewhat “damp” at pole. To be minable it need to be about 5% per volume
of water. And somewhat dry dirt on Earth has about this amount of water in it. Mars compare to Earth is very dry, but compared to the Moon, fairly wet.
So asteroid of main asterisk belt probably have far less water than Earth, but all asteroid in solar system- particularly if include in the count all dwarf planets like Ceres- which have yet to be discovered- probably has many thousands of times the amount water as Earth.
Chad Wozniak says:at 7:53 pm
Clarke and Baxter’s “The Light Of Other Days” provides a narrative that allows one to envision the depth of time that our planet has experienced, and the evolution that may have occurred between the various climactic ages. Highly recommended!
I have read it… excellent book.
MattS says:
January 30, 2014 at 7:19 pm
Goldie
“The Earth as we know it is the outcome of a series of massively improbable events:”
We have no way of knowing how improbable those events are in the larger galaxy / universe.
The only empirical evidence we have is our own solar system. Odds of 1 in 8, 1 in 9 or 1 in 10 depending on how you want to count planets. Odds of 1 in 10 do not count as massively improbable in my book.
You always exclude the observer when gathering stats on any population. If you’re, say, gathering statistics on the average number of customers in, say, a restaurant, you should not count yourself.
Now, since our planet seems to occupy a piece of prime real estate in terms of distance from the sun (and two planets cannot, by definition, cannot share) the life being “oh fer” all the others doesn’t tell us much either.
Better estimate is 3-4 billion years ago for the first plants. A little after the moon-earth collision about 4.3 – 4 billion years ago that basically blew a large part of the crust away. The earliest fossils I have on the shelf are those of the first oxygen-releasing “plants”. Best we can tell tell, the earliest atmosphere was opaque – absorbing all transmitted (visible) light .. until the plants grew and cleared the atmosphere into its present 21% – 78% mix of (transparent) gasses.
The probability is actually much larger against any local equivalent life-as-we-know-it planet:
Graphically, http://xkcd.com/1298/
It must be noted that this is all speculation based on the new finding of a variety of types of asteroids, which could mane all sorts of things. They talk of Jupiter wandering in among the terrestrial planets and yet there is no evidence of that whatsoever. it is just scientists speculating.
Speculation is not science.
People here at WUWT should be well aware of that by now.
“Best we can tell tell, the earliest atmosphere was opaque – absorbing all transmitted (visible) light .. until the plants grew and cleared the atmosphere into its present 21% – 78% mix of (transparent) gasses.”
To sunlight CO2 is slightly more transparent than nitrogen and/or oxygen.
The only reason for Earth being opaque would due to dust [- including volcanic pollution].
But in terms of million of years rather centuries- thousands of years high levels of volcanic activity, earth skies should have as clear to sunlight as current atmosphere.
Some think there may have been more atmosphere- if you had 2 or 3 more nitrogen
it would slightly be dimmer, particularly morning late afternoon.
Chad Wozniak
January 30, 2014 at 7:53 pm
says:
@Tom J –
Thanks for the comment. I was actually sort of kidding with my earlier comment, although the part about the Earth being a bigger target for asteroid hits is in the literature as one of the litany of horrors CO2 causes.
Best wishes.
RACookPE1978 said:
January 30, 2014 at 8:20pm
“…the earliest atmosphere was opaque – absorbing all transmitted (visible) light .. until the plants grew and cleared the atmosphere…”
——–
If the atmosphere was opaque (sunlight could not penetrate), then how could photosynthesis have arisen? Plants grew in an environment of no light?
Sorry, I must not be understanding something.
RACookPE1978,
That is nothing more that a bit of speculation that presumes that we do/can know the probability of any particular star having an earth like planet within the appropriate orbital range. The ability to actually detect exo-planets is still in its infancy and the probabilities are a complete unknown.
We live in an average galaxy orbiting an average star. What? Are we in the teenage of astronomy? Questioning whether we are more strange or weird compared to the other kids? Later we find out we’re quite normal.
What might be unusual about Earth is our Moon. It seems to me the stability our companion gives us has helped make the biosphere more stable. In particular, it has given us a chance to develop intelligence and a civilization. That part might be very unusual.
It’s why I find it terribly dangerous to denigrate the important role of humans on Earth. We represent perhaps the only chance for Earth to spread the seeds of life far from this planet. If we fail, will there ever be another chance for a second intelligent species to rise up and do the job?
Don’t we have a duty to use the energy stored on Earth for millions of years for the ultimate valuable purpose? In the same way, trees and other plants devote large amounts of energy to reproduction. It is only natural we carry out the natural process of seeding life on other worlds. That’s what life does. Seeds and animals travel across oceans to start a new life on islands. Space is the next ocean we (more than just humans) need to cross.
It turns out what we are doing with science and technology is exactly natural.
Gary Pearse wrote –
“Yeah, average granite magmas have about 5% water. This is the trouble with astronomers speculating on earth science. They linearly think the stuff has to rain down only from above. Also, why would the snowballs wait so patiently for the earth to be fully formed before they attacked. Hey, there must have been even more of them in the earlier chaotic period while the earth was agglomerating.”
Astronomers indeed !,in a forum that can’t appreciate the most basic of basic correlations between daily temperature fluctuations and the rotational cause behind it,how is it possible to discuss the neat meshing of the 26 mile spherical deviation of the planet with crustal evolution and motion using a common rotational mechanism.
Grow up for goodness sake ! ,the Earth is not a ‘rocky planet’, it has a huge rotating viscous mass with a very thin fractured crust and especially oceanic crust. All rotating celestial objects with exposed viscous compositions display an uneven rotational gradient between Equatorial and Polar latitudes and with all the clues imprinted on the Earth surface crust,and especially the Mid Atlantic Ridge, there is every reason not to exempt the Earth from the same rotational feature of all rotating celestial objects.
Astronomers !, what astronomers ?. There are plenty of theorists chanting voodoo at the celestial arena and living off the using doom laden predictions but not a single one who can interpret a basic temperature graph as a signature of planetary dynamics. Turns out that this forum is no better or worse than their opponents in this respect.
“Predators are generally smarter than prey….”
Or animals that catch gras for a living don’t need to be smart?
““…the earliest atmosphere was opaque – absorbing all transmitted (visible) light .. until the plants grew and cleared the atmosphere…”
——–
If the atmosphere was opaque (sunlight could not penetrate), then how could photosynthesis have arisen? Plants grew in an environment of no light?”
I think what they mean with opaque is that you couldn’t see earths surface from space. Just like Venus today. That doesn’t mean that sunlight didn’t reach earths surface?
Another thing, didn’t it start with plankton in water?
Early Sun underwent a violent T Tauri stage. During that time magnetohydrodynamics played a central role in the formation of the system by transferring a huge amount of angular momentum outward to the protoplanetary disk, which can’t be done by gravitational forces alone.
Now, magnetohydrodynamics leads to notoriously intractable mathematical problems, so I do not think it is possible to construct an adequate reductionist computational model of solar system formation.
This is just Velikosky revisited all over again.
There are three issues that killed off Worlds in Collision the first time:
1 There’s just no evidence that it ever happened.
2 Isn’t it weid how we ended up with all the gas giants in the outside and the rocky planets tidily in the middle if the gas giants can wander? How very tidy. (Now stronger as some exoplanets show gas giants near their sun so there’s no tidyng tendency).
3 How come so few asteroids were sent out of the plane of the solar system? Some were, so it can happen, but Jupiter seemed to have missed nearly everything on its meanderings.
Is there anything here to overcome the three issues?