Experiment Recreates Asteroid Collision With Earth That Killed Off the Dinosaurs

An experiment that recreated the impact of an asteroid with the Earth that led to the extinction of the dinosaurs was done by researchers from the University of Exeter, University of Edinburgh and Imperial College London.

The scientists used a fire propagation apparatus to recreate the thermal pulse generated by an asteroid collision. Halogen lamps were also utilized to simulate the delivering thermal radiation (see image).

The experiment revealed that the long standing theory that the collision created firestorms around the Earth proved false. The heat generated by the experiment showed that the actual asteroid impact would have generated a heat pulse that lasted less than a minute. That is not enough time to ignite live plants.

Dr Claire Belcher from the Earth System Science group in Geography at the University of Exeter said, "By combining computer simulations of the impact with methods from engineering we have been able to recreate the enormous heat of the impact in the laboratory. This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact. This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event."

Information Found Inside Meteorite Gives Insight To Earth's Freezing Core

Researchers have captured information stored inside tiny magnetic regions in meteorite samples using a detailed imaging technique at the BESSY II synchrotron in Berlin.

Meteorites are fragments of asteroids formed in the early solar system. The asteroids were heated up by radioactive decay, causing them to melt and segregate into a liquid metal core surrounded by a solid rocky mantle. The convection of the liquid metal generates a magnetic field similar to how the Earth's magnetic field is created.

The information found by the team relays the magnetic field of the meteorite during core solidification on its parent body. These magnetic field readings provides a brief glimpse on the Earth's own magnetic field as the Earth's core continues to freeze.

The meteorites used are called Pallasite Meteorites which are made up of iron and nickel. The body of pallasite meteorites are studded with silicate crystals that resemble gems. The team found that along with iron and nickel, there are also tiny nanosized minerals called tetrataenite. These tetrataenites are just around 100 nanometers long which is magnetically much more stable than the rest of the meteorite, and holds within it a magnetic memory that the researchers have gathered.

The data shows that the magnetic fields generated by the asteroids lasted longer than expected; about several hundred million years after the it formed. The results help to answer many of the questions surrounding the longevity and stability of magnetic activity on small bodies, such as asteroids and moons.

Scientists now think that the Earth's core only began to freeze relatively recently in geological terms, maybe less than a billion years ago. How this freezing has affected the Earth's magnetic field is not known. "In our meteorites we've been able to capture both the beginning and the end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future," said Dr Richard Harrison of Cambridge's Department of Earth Sciences, who led the research.

Probing the Secrets of Asteroid Itokawa

Schematic of Asteroid Itokawa

Using the New Technology Telescope (NTT) by the European Southern Observatory, scientists have, for the first time, studied the internal structure of an asteroid.

The NTT studied the peanut shaped asteroid Itokawa. It helped scientists measure the asteroid's brightness variation as it rotates. Knowing the irregular peanut shape of Itokawa, the data gathered allowed them to accurately calculate its spin period. This also gave the scientists an insight to find out what the asteroid is like below the surface and also at its core.

This discovery, already a big step in understanding asteroids, will also help understand how planets are formed and what happens during outer space collisions.

Defending The Earth Against Incoming Asteroids Using Paintballs

An MIT graduate student proposes covering Earth bound asteroids with paint using paint pellets and paint balls to deflect its trajectory from hitting our planet.

The Earth has always been in danger of being hit by large space objects such as comets and asteroids. The extinction of the dinosaurs 65 million years ago, is said to have been caused by an asteroid ten to fifteen kilometers wide hitting the Earth.

According to Nick Bostrom who did a study on human extinction scenarios and its related hazards, every 500,000 years, an asteroid 1km in diameter strikes the earth and a 5km asteroid every ten million years. To get an idea on how powerful asteroids of this size are, a five to ten meter asteroid packs as much power as an atomic bomb.

Apophis

Asteroid 2004 MN4 known as Apophis has a diameter of 270 meters and weighs around 27 gigatons. One gigaton is one billion tons (1x10⁹). According to its present trajectory, Apophis will have a close call with the Earth on Friday, 13 April 2029.

MIT News: Asteroid Vesta Once Had Dynamo That Generated Magnetic Field Like The Earth

On September 27, 2007, NASA launched its Dawn spacecraft. Its mission is to orbit the asteroid Vesta and then head over to another asteroid, Ceres.

Both Vesta and Ceres are situated in the asteroid field between Mars and Jupiter. Dawn's goal is to investigate in detail the two asteroids which are the largest protoplanets still intact. Protoplanets are small celestial bodies that show the beginning formation of a planet. These are differentiated objects which means, that these protoplanets underwent a process where their interior got hot enough to melt separating elements within into layers.

Vesta is a dry, differentiated object that has a rocky surface which resemble some features found on the Earth.

Last year, data from the Dawn mission revealed that Vesta may be the smallest terrestrial planet in the solar system. Meteorites found on Earth believed to have come from Vesta has shown extensive igneous processing not much different from the magma rocks found on Earth. This process makes them closely resemble terrestrial igneous rocks.

Japan Space Agency JAXA To Launch Spacecraft Hayabusa 2 To Rendezvous With Asteroid

Artist rendition of Hayabusa 2 departing from Earth
Credit: Hayabusa 2 project

The Japan Aerospace Exploration Agency (JAXA) is Japan's national aerospace agency. It was formed on October 01, 2003 and administered by the country's Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Ministry of Internal Affairs and Communications (MIC).

The responsibility of the agency is the research, development, and launch of satellites into orbit. Not confined to those projects, they are also actively involved in other missions such as asteroid exploration and possible manned exploration of the Moon.

JAXA's Hayabusa mission (launched 2003, returned 2010) was the first spacecraft ever to collect samples from an asteroid and return to Earth successfully. The target of the asteroid probe was Itokawa, an asteroid with a diameter of 500 meters. Using Earth's gravitational field and ion engines, Hayabusa reached the asteroid and provided scientists a first close look of a Near Earth Object(NEO).

Japanese spacecraft to search for clues of Earth's first life

Physics World's Dennis Normile reports that Japanese space agency, JAXA, plans to land a spacecraft on an asteroid in 2018. Its goal is to look for clues on how life began on Earth.

The spacecraft, named Hayabusa 2, is the second mission of JAXA at investigating and collecting data from an asteroid. The first mission, Hayabusa, returned to Earth in June 2010. Hayabusa 2 will be launched in 2014 with a view to settling on the targeted asteroid, named 1999 JU3, in mid-2018 before arriving back on Earth in 2020.

Hayabusa 2 will fire fingertip-sized bullets into the surface of the asteroid and the fragments from the impact will be collected. It will also detonate an impactor module, which will fire a 2 kg projectile into the asteroid to create a 2 m crater.

Meteorites From Asteroid Vesta May Give Clues To Origin of the Solar System

The giant asteroid Vesta is shown here as the smallest body among other similar bodies in the solar system - Mars, Mercury, Earth's moon and the dwarf planet Ceres
Image: NASA

A subgroup of achondrite meteorites are Howardite-Eucrite-Diogenite meteorites. Commonly reffered to as HED meteorites, these come from a differentiated parent body.

Differentiation is the process when the interior of an active planet gets hot enough to melt. As it melts, it separates its materials into layers. The light material floats to the top while the heavy elements, such as iron and nickel, sink to the center of the planet. They believe that this also happened to Vesta.

HED meteorites have experienced extensive igneous processing not much different from the magmatic rocks found on Earth. This process makes them closely resemble terrestrial igneous rocks

A subgroup of HED, diogenites are believed to originate from the asteroid Vesta. These are composed of igneous rocks of plutonic origin. A pluton is a body of igneous rock (called a plutonic rock) that has crystallized from slowly cooling magma.

Diogenites have solidified slowly enough deep within Vesta's crust to form crystals. These crystals are primarily magnesium-rich orthopyroxene, with small amounts of plagioclase and olivine.

New clues to the early Solar System from ancient meteorites

In order to understand Earth's earliest history--its formation from Solar System material into the present-day layering of metal core and mantle, and crust--scientists look to meteorites. New research from a team including Carnegie's Doug Rumble and Liping Qin focuses on one particularly old type of meteorite called diogenites. These samples were examined using an array of techniques, including precise analysis of certain elements for important clues to some of the Solar System's earliest chemical processing. Their work is published online July 22 by Nature Geoscience.

At some point after terrestrial planets or large bodies accreted from surrounding Solar System material, they differentiate into a metallic core, asilicate mantle, and a crust. This involved a great deal of heating. The sources of this heat are the decay of short-lived radioisotopes, the energy conversion that occurs when dense metals are physically separated from lighter silicate, and the impact of large objects. Studies indicate that the Earth's and Moon's mantles may have formed more than 4.4 billion years ago, and Mars's more than 4.5 billion years ago.

Theoretically, when a planet or large body differentiates enough to form a core, certain elements including osmium, iridium, ruthenium, platinum, palladium, and rhenium—known as highly siderophile elements—are segregated into the core. But studies show that mantles of the Earth, Moon and Mars contain more of these elements than they should. Scientists have several theories about why this is the case and the research team—which included lead author James Day of Scripps Institution of Oceanography and Richard Walker of the University of Maryland—set out to explore these theories by looking at diogenite meteorites.

Carbonaceous chondrites and Asteroids Most Likely Source of the Earth's Water

The Allende meteorite is the largest carbonaceous chondrite ever found on Earth.

Chondrites are meteorites that have not been tampered or modified due to melting or differentiation of the parent body. These type of meteorites form when various types of dust and small grains that were present in the early solar system gradually accumulate to form primitive asteroids.

Chondrites should not be confused with Chondrodite which is a rare nesosilicate mineral.

A class of chondritic meteorites are Carbonaceous chondrites or C chondrites. These comprise at least 7 known groups of meteorites and other ungrouped meteorites. Only 4.6% of meteorite falling to Earth are Carbonaceous chondrites

Solar system ice: Source of Earth's water

Scientists have long believed that comets and, or a type of very primitive meteorite called carbonaceous chondrites were the sources of early Earth's volatile elements—which include hydrogen, nitrogen, and carbon—and possibly organic material, too. Understanding where these volatiles came from is crucial for determining the origins of both water and life on the planet. New research led by Carnegie's Conel Alexander focuses on frozen water that was distributed throughout much of the early Solar System, but probably not in the materials that aggregated to initially form Earth.

The evidence for this ice is now preserved in objects like comets and water-bearing carbonaceous chondrites. The team's findings contradict prevailing theories about the relationship between these two types of bodies and suggest that meteorites, and their parent asteroids, are the most-likely sources of the Earth's water. Their work is published July 12 by Science Express.

Looking at the ratio of hydrogen to its heavy isotope deuterium in frozen water (H2O), scientists can get an idea of the relative distance from the Sun at which objects containing the water were formed. Objects that formed farther out should generally have higher deuterium content in their ice than objects that formed closer to the Sun, and objects that formed in the same regions should have similar hydrogen isotopic compositions. Therefore, by comparing the deuterium content of water in carbonaceous chondrites to the deuterium content of comets, it is possible to tell if they formed in similar reaches of the Solar System.

Rock Layers Show Evidence of Heavy Asteroid Impacts During the Archeon Era 3.8 Billion Years Ago

The Archeon Eon lasted 1.5 Billion years. It preceded the Phanerozoic eon.

During the Archeon eon, Earth's atmosphere is very different to present day Earth. The atmosphere would be comprised of methane, ammonia and other toxic gases. This was the time that the Earth's crust cooled enough for plate tectonics to form rocks and continental plates.

The oldest fossils (cyanobacterial mats or stromatolites) discovered was dated during the Archean eon, roughly around 3.5 billion years. These colonies of stromatolites are simple photosynthetic bacteria that was responsible for releasing oxygen in the atmosphere. Stromatolites have been found as fossils in early Archean rocks of South Africa and western Australia. Stromatolites increased in abundance throughout the Archean, but began to decline during the Proterozoic.

Splatters of molten rock signal period of intense asteroid impacts on Earth

New research reveals that the Archean era — a formative time for early life from 3.8 billion years ago to 2.5 billion years ago — experienced far more major asteroid impacts than had been previously thought, with a few impacts perhaps even rivaling those that produced the largest craters on the Moon, according to a paper published online today in Nature.

The fingerprints of these gigantic blasts are millimeter- to centimeter-thick rock layers on Earth that contain impact debris: sand-sized droplets, or spherules, of molten rock that rained down from the huge molten plumes thrown up by mega-impacts. This barrage of asteroids appears to have originated in an extended portion of the inner asteroid belt that is now mostly extinct. Computer models suggest the zone was likely destabilized about 4 billion years ago by the late migration of the giant planets from the orbits they formed on to where we find them today.

The team conducting this study includes members or associates of the NASA Lunar Science Institute's Center of Lunar Origin and Evolution (CLOE), based at the Southwest Research Institute (SwRI) in Boulder, Colo.

Archean rocks are scarcer than rocks of any other age, and impact spherule beds have been found only in terrains where conditions were ideal for capture and preservation, such as in shales deposited on the seafloor below the reach of waves. At least 12 spherule beds deposited between 3.47 and 1.7 billion years ago (Ga) have been found, with most in the Archean; 7 between 3.23-3.47 Ga, 4 between 2.49-2.63 Ga and 1 between 1.7-2.1 Ga.

Defending The Earth From Asteroids

On Friday, 13 April 2029, Asteroid 2004 MN4 also known as Apophis, will have a close encounter with the Earth.

The asteroid will not hit the Earth.

It will be so close to the Earth that the asteroid will be passing below the communication satellites orbiting the Earth. On April 13, 2029, Apophis will fly past the Earth 18,600 miles above it. The satellites orbit at 22,300 miles.

Although the asteroid will narrowly miss the Earth, there is a small complication. It may collide with the Earth seven years later.

Upon passing the Earth, if Apophis passes thru a certain region of space above the planet called the Keyhole, which is about 600 miles wide, seven years later on April 13, 2036, the asteroid will directly collide with the Earth. April 13, 2036 is also a Friday. There is a 1 in a million chance that the asteroid will pass thru the keyhole.

Video: Neil DeGrasse Tyson discusses Apophis and the destruction it can bring

Apophis is around 1,150 (350 meters) feet in diameter, bigger than a football field. It's not big enough to wipe out civilization but can cause serious damage. The impact can be comparable to detonating a 510 megatons of TNT. In comparison, the biggest hydrogen bomb ever exploded was 50 megatons.

Scientists all over are busy finding ways to avert this disaster. China's Tsinghua University proposed launching an impactor spacecraft in a retrograde orbit, steered and powered by a solar sail. The spacecraft will move the asteroid away from the gravitational keyhole. As mentioned by Phil Plait in the video, another solution is to launch a probe that will hit the asteroid first then launch another one that will safely "tow" the asteroid away from the Earth using an ion drive. There may even be a possibility of towing it to orbit the Earth in order to mine the asteroid for minerals.

Video: Phil Plait talks about asteroid impacts, Apophis and ways to avoid a collision.

The B612 Foundation, a private foundation dedicated to protecting the Earth from asteroid strikes, estimated that if an impact with Apophis does occur, the path of the collision extends across Southern Russia, the north Pacific (near Californa and Mexico) then between Nicaragua and Costa Rica crossing Colombia and Venezual ending in the Atlantic before reaching Africa.