Was the Moon Created by a Giant Collision? German Scientists Say Most Deff

 

Most theories about the formation of the Moon use a "Huge Impact" a a probable cause for the Moon's creation.  Problem? Oh yes, analysis of samples from the moon show that they are identical with those of Earth's.  No third planet material is detected in either samples, which is a major setback to proving said theory.  

Now a German team has re-examined the moon rock samples and discovered a measurable difference in the ratio of Oxygen isotopes with the samples having a slightly higher concentration of Oxygen 17 than Earth rock does, which the researchers claim is evidence that a rogue planet played a part in the formation of the moon.

Of course not everyone is sold.  Critics of the updated huge impactor suggest that they would    expect a more radical difference in chemical compositions between Earth and the theoretical huge asteroid.  The German team also had only a small sample set to work with, but the lead researcher is pretty convinced: "This confirms the giant impact hypothesis."

Oldest Impact Crater Discovered

Unlike the airless bodies in the Solar System, The Earth as a general example shows evidence of the massive and violent bombardment several billion years ago. Finding any evidence of ancient bombardment is more a scientific version of poke and hope. Continental drift plus the effects of rain, wind, plus the effects of the seasonal weather erase many of the structures that identify an impact crater.
From the article:

• Now, an international team of scientists say they have found a massive impact crater in Greenland a billion years older than other known asteroid impact on Earth.

The crater is located in the Maniitsoq region of West Greenland and is roughly one billion years older that the next oldest crater. What is truly amazing though is the huge diameter of the Greenland impact which measures a stunning 62 miles across!

Craters of the age of the Greenland impact have been all but obliterated, however the crust around Greenland:

• has been eroded over the eons to expose crust that originally was 16 miles below the surface. Effects of the immense shock-wave produced on impact penetrated deep into the crust and remain visible.

read the complete article here

Deep Impact Hoping for a Third Mission Extention

NASA's Deep Impact spacecraft fired its on-board rocket motors Thursday, Nov. 24 for just over 2 minutes. This burn was done on hopes that NASA will once again extend the spacecraft's mission one more time. If so, then Deep Impact will again fire its engines sometime next fall.

Since its mission completion in 2005 encounter with comet Tempel 1, Deep Impact has done a flyby of Hartley 2 on Nov. 4, 2010. Its present burn resulted in a delta V of only 19.5 mph but should keep many options open should NASA agree to the mission extension.

Complete Science Daily article here

Did all life on Earth Almost End Recently?

Remember hearing about that group of comets, back in August of 1883? They were so huge and coming in so close that folks were taking out comet insurance. Mexican astronomer José Bonilla, observed 447 objects passing in front of the sun over two days. But this huge amount of material could not be found by any other astronomers. Or even be seen, they suggested all form of fauna and flora that could have been miss read. What Bonilla observed were actually fragments of a massive, billion-ton comet, and the reason that no one else was able to observe the objects is that they passed so close to the Earth!

Calculations show that the ultra massive object passed between 300 to 5000 miles above the surface!!

From the Gizmodo article:

• The impact at Tunguska was by moderate estimations about 15 megatons, or 1,000 times more powerful than Hiroshima. 3,275 of those bombarding the planet over two days would likely be, as the authors of the paper put it, "an extinction event."
• 
  

Deep Impact Still Making History / UPDATE!!!

For only the fifth time in the history of the space program, a spacecraft will fly close enough to image a comet. The probe Deep Impact first made history when it launched an 800 pound impactor into the comet Tempel 1, July fourth of 2005 totally changing what we thought we knew about the makeup of the comet.

That impact was supposed to be the end of the spectacularly successful 300 million dollar mission. However NASA gave mission controllers permission to go for another close encounter with a comet and JPL decided that a comet discovered 24 years ago was a good candidate. This comet was Hartley2 discovered by Malcom Hartley using the Schmidt Telescope in Australia.

At 7:00am on Thursday November fourth, Deep Impact Extended investigation ( DIXI) will approach the comet within apx 400 miles, taking pictures along the way.

NASA's Goddard Space Center article Wiki Deep Inpact and DIXI mission

And here are some spectacular photos from Comet Hartley 2

Animation of a 300 mile asteroid hitting Earth

I know, I always seem to gravitate to these type of disaster videos. I have to say that this is one of the better that I first found on Pink Tentacle. It is a simulation of what it would be like should a 300 mile wide asteroid hit Earth. The PT article says that this video was "produced by NHK Japan and the National Film Board of Canada..." It's from a longer piece, but this 10 minute selection makes you nostalgic for the good ole days of global warming!

Researchers Certain: Chicxulub event did wipe out the dinowsaurs

In a review, published online March 4 in Science, a team consisting of 41 researchers, have decided that the 30 year old paper by father and son research team Luis and Walter Alvarez, was indeed, a massive asteroid that slammed into Earth, creating Chicxulub Crater on Mexico's Gulf Coast, that killed off many of the species on the planet, including the non-avian dinosaurs.

The team looked at:

Volcanism that produced the great Deccan Trap formation, and Multiple asteroid impacts, involved in the extinction event, and concluded that these possible causes are to inconclusive and in some instances may actually made conditions on Earth MORE favorable for life.

Read the complete article in Scientific American here

Jupiter just took a pounding, Is Earth next?

Since the huge impact on Jupiter is still fresh in our memories, I think it's fair to ask - what are the chances that the same could befall Earth any time in the near future?

Tim Sayell send in a good article from Yahoo News that deals with just such a question.

As the article points out: So far 784 near-Earth objects (NEOs) more than a half-mile wide (1 km) have been found. NASA has ruled out any of these as an impactor.

It's a safe bet that if 'an object of about the same size that just hit Jupiter also hit Earth — it was probably a typical cometary object of a kilometer or so in size (0.6 miles) — it would have been fairly catastrophic,'

Currently just one NEO poses any significant chance of hitting the Earth — 2007 VK184. This object is 425-foot-wide and should it hit Earth, it would strike with an energy of more than 10,000 times that of Hiroshima. 2007 VK184 has a 1-in-2,940 chance of hitting Earth 40 to 50 years from now.

Like the mosquito that you don't hear, it's the NEOs that we don't know about that are most worrying. NASA estimates that there are about 156 large NEOs 1 kilometer in diameter or larger that remain to be found. But the truly disturbing statistic is that objects of about 500 feet are extremely dangerous and only about 15% of these object have been discovered and only 5% of objects 150 feet in size.

Now the nitty gritty:
The dinosaur killers happen about once every 100 million years
Impacts of 1500 foot size hits about once every 500,000 years...so nothing is expected soon...
150 feet, about 700 years, 98 feet about 140 years or so.

So, nothing really worrisome with what we know so far....but a lot more has to be put into discovery and tracking before I feel safe.

Read the complete article here

Could balast weights some day save the Earth?

According to a doctoral candidate in aerospace engineering at North Carolina State University. David French's novel approach to preventing an asteroid from impacting Earth is to attach a long tether and ballast to incoming objects - thereby changing the object's center of mass, effectively changing the object's orbit. Of course the tether would be astounding in length - in the order of 600 to 60 thousands miles!

Brings to mind the scale and scope of the proposed space elevator.

Read the complete Science Daily article

Ocean Impacting Asteroid Won't Kill Us - Quickly

An asteroid falling int the ocean will not wipe out life on Earth, at least not immediately. This according to a recent article in IO9 . Scientists from the University of Oslo have been running simulation of an asteroid apx. 1000 feet across hitting the ocean and the new results seem to indicate that not all is lost.

From the article:

• The impact initially sends waves hundreds of metres high spreading from the impact site. However, the very height of the waves makes them prone to collapse even in very deep water: they start breaking immediately, like ordinary waves on a beach.
• By the time they are 30 kilometres from the impact site, they have shrunk to a height of less than 60 metres

Of course there would be other effects, like hurricane force winds and lots of water falling.

Read complete article in IO9

How Best To Avoid Asteroid Apocalypse

Here is an novel approach to avoiding Earth getting spanked by a dino killer. This clever solution came to my attention in an article on the IO9 blog. It comes from David Dearborn, at the Lawrence Livermore National Laboratory in California. Dearborn's proposal has all the making of a really good Willis movie. You know....multi-megaton bombs.... but with a teny tiny difference you see. The first is that David's plan takes place 30 years before impact. In astrological distances it's right freakin on top of us, but for the movies, 30 years....well that's like another century right?!

Anyway, here is how it works, and its brilliant in its simplicity! Instead of blowin it up, or throwin things at it, or putting rocket engines on it, or tractors....we speed it up! Oh I hear the howls "what you want it to get here quicker!!!!??" But that is exactly what Dearborn wants. If it gets here sooner, we won't be here yet! You take a 100 kiloton bomb and explode it about 3 or 4 football fields behind the impactor. This isn't enough to blow it up, matter of fact - simulations have only 1% of the asteroid dislodged. But it is enough to speed the asteroid up. How much? About 6.3mm/s or about 1.25 feet per minute. Not much huh? But over a 30 year period the Earth won't even be close!

But it's an honest and workable idea. Read the IO9 article

NASA spacecraft document largest crater in Solar System

NASA's Mars Reconnaissance Orbiter and Mars Global Surveyor have provided detailed information to what seems to be the largest impact crater ever found in the solar system. Last March, I ran an article that spoke about the lack of symmetry between Mars' northern and southern hemispheres. At that time there was conjecture that this deformation might have been caused by an asteroid impact, however there was some skepticism because the formation in the northern area was not in the shape that one would expect from such an impact. However the new information from the orbiters is creating intense scientific interest in the huge crater. The northern crater takes the shape of a giant basin that covers about 40 percent of Mars' surface, sometimes called the Borealis basin, and is now almost certainly the remains of a colossal impact early in the solar system's formation. At 5,300 miles across, it is about four times wider than the next-biggest impact basin known, the Hellas basin on southern Mars. What's even more amazing is the impactor would have been in the order of 1,200 miles across, making it larger than Pluto! What's more huge object lowered Mars' northern hemisphere between 2 and 5 kilometers!

<NewScientist article>
<More from NASA>

Mirrors 'could deflect' asteroids

From BBC News

Orbital mirrors could save earth from a catastrophic asteroid collision, researchers have claimed. Up to 5,000 mirrors would be used to focus a beam of sunlight on to the asteroid, melting the rock and altering its orbital path away from earth. Orbiting mirrors would be used to focus sunlight on an area of the asteroid - heating the rock to around 2,100 degrees Celsius. This would create a thrust which would nudge the asteroid off course. An asteroid 150m across could be sufficiently modified by a swarm of 100 mirrors in a few days.

Thanks to Shaun Saunders for the post

Deep Impact probe gets new mission

NASA announced Tuesday that it has accepted a proposal by the University of Maryland, which developed and manages Deep Impact, to send the vehicle on an extended mission to intercept Comet Boethin.

The spacecraft remains healthy so the surviving portion of the Deep Impact space probe that watched as its other half smashed into a comet on July 4 is being sent on a mission to study another comet.

The new mission won't involve a collision. Instead, Deep Impact will pass Boethin in December 2008 so its instruments can examine the comet.