Free Republic

Days on Earth are getting longer as the moon slowly moves farther away from us, new research shows.  The moon is about 4.5 billion years old and resides some 239,000 miles (385,000 kilometers) away from Earth, on average. However, due to tidal forces between our planet and the moon, the natural satellite slowly spirals away from Earth at a rate of about 1.5 inches (3.82 centimeters) per year, causing our planet to rotate more slowly around its axis.  Using a new statistical method called astrochronology, astronomers peered into Earth's deep geologic past and reconstructed the planet's history. This work revealed...

Over the course of the past 200 million years, our planet has experienced four major geological periods (the Triassic, Jurassic and Cretaceous and Cenozoic) and one major ice age (the Pliocene-Quaternary glaciation), all of which had a drastic impact on plant and animal life, as well as effecting the course of species evolution. For decades, geologists have also understood that these changes are due in part to gradual shifts in the Earth’s orbit, which are caused by Venus and Jupiter, and repeat regularly every 405,000 years. But it was not until recently that a team of geologists and Earth scientists...

In such a scenario, scientists expect that about a fifth of the Moon's material would have come from Earth and the rest from the impacting body. The Moon, our planet's constant companion for some 4.5 billion years, may have been forged by a rash of smaller bodies smashing into an embryonic Earth, researchers have revealed. A bombardment birth would explain a major inconsistency in the prevailing hypothesis that the Moon splintered off in a single, giant impact between Earth and a Mars-sized celestial body. In such a scenario, scientists expect that about a fifth of the Moon's material would have...

In recent decades the scientific consensus has been that the moon formed billions of years ago from debris cast off when a Mars-sized object dealt Earth a glancing blow. But a radical new theory holds that some long-ago giant collision actually disintegrated Earth, causing it to balloon out into a vast doughnut-shaped cloud of vaporized rock, which the scientists who developed the theory dubbed a “synestia." They say the moon subsequently formed within this cosmic maelstrom. In the long-accepted explanation of lunar formation, the collision between Earth and the Mars-sized object, known as Theia, ejected part of Earth's mantle —...

Over two centuries ago, Pierre-Simon Laplace, a French physicist and mathematician, noticed that the Moon's equatorial bulge is about 20 times larger than expected. Now, researchers are trying to find out why. Although the Moon looks quite spherical from the ground, it is flatter at its poles and wider at its equator, a trait known as an equatorial bulge. This characteristic is common; it's usually caused by an object's rotation around its axis. However, it's been noted that the Moon's bulge is about 20 times larger than it should be given its rotational rate of once per month... researchers at...

Researchers say life-bearing planets may exist in vast numbers in the space between stars in the Milky WayA few hundred thousand billion free-floating life-bearing Earth-sized planets may exist in the space between stars in the Milky Way. So argues an international team of scientists led by Professor Chandra Wickramasinghe, Director of the Buckingham Centre for Astrobiology at the University of Buckingham, UK. Their findings are published online in the Springer journal Astrophysics and Space Science. The scientists have proposed that these life-bearing planets originated in the early Universe within a few million years of the Big Bang, and that...

Explanation: What is the history of the Moon? The Moon was likely created from debris expelled when a Mars-sized object violently impacted the Earth about 4.5 billion years ago. Just after gravitationally condensing, as imagined above, the glowing-hot surface of the Moon cooled and cracked. Rocks large and small continued to impact the surface, including a particularly large impact that created Aitken Basin about 4.3 billion years ago. A Heavy Bombardment period then continued for hundreds of millions of years, creating large basins all over the lunar surface. Over the next few billion years lava flowed into Earth-side basins, eventually...

According to a new study conducted by an international team of scientists, it may have something to do with a massive impact that occurred in the past. Since Venus appears to have never suffered such an impact, its never developed the dynamo needed to generate a magnetic field. ... According to the most widely-accepted models of planet formation, terrestrial planets are not formed in a single stage, but from a series of accretion events characterized by collisions with planetesimals and planetary embryos – most of which have cores of their own. Recent studies on high-pressure mineral physics and on orbital...

Heavenly bodies stir up routine catastrophes March 18 2003 at 01:30PM By Graeme Addison Legend has it that when two people get together and er... bond, the Earth will move – at least in a metaphorical sense. Likewise, it takes two heavenly bodies, an impactor and a target, to come together with Earth-shattering force to form a crater. There’s nothing dreamlike about this: it happens, frequently, throughout the solar system. Impact catastrophes are routine. Just over two-billion years ago, a chunk of asteroid at least the size of Table Mountain struck the landmass that is now South Africa. It hurtled...

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... It has been suggested that both comets and carbonaceous...

Impact cratering is one of the most fundamental geological processes. On many planets, impact craters are the dominant geological landform. On Earth, erosion, plate tectonics, and volcanic resurfacing continually destroy the impact cratering record, but even here, the geological, biological, and environmental effects of impact cratering are apparent. Impact events are destructive and have been linked to at least one of the 'big five' mass extinctions over the past 540 million years. Intriguingly, impact craters can also have beneficial effects. Many impact craters are associated with economic metalliferous ore deposits and hydrocarbon reservoirs. This Special Paper from The Geological...

Moon rocks delivered to Earth by Apollo astronauts held a mystery that has plagued scientists since the 1970s: Why were the lunar rocks magnetic? Earth's rotating, iron core produces the planet's magnetic field. But the moon does not have such a setup. Now, scientists at MIT think they have a solution. Some 4.2 billion years ago, the moon had a liquid core with a dynamo (like Earth's core today) that produced a strong magnetic field. The moon's magnetic field would have been about 1-50th as strong as Earth's is today, the researchers say. The MIT team found evidence for the...

A smattering of water is buried deep inside the Moon and it arrived during the satellite's very early history, a new study concludes, when asteroids plunged into its churning magma oceans. How and when water got trapped in volcanic lunar rocks is a huge and open question for planetary scientists.

A new chemical analysis of lunar material collected by Apollo astronauts in the 1970s conflicts with the widely held theory that a giant collision between Earth and a Mars-sized object gave birth to the moon 4.5 billion years ago.

Lunar swirls can be tens of miles across and appear in groups or just as an isolated feature. Previous observations yielded two significant clues about their formation: First, they appear where ancient bits of magnetic field are embedded in the lunar crust (although not every “fossil” magnetic field on the moon has a lunar swirl). Second, the bright areas in the swirls appear to be less weathered than their surroundings. The space environment is harsh; many things can cause material exposed to space to change chemically and darken over time, including impacts from microscopic meteorites and the effects of the...

New NASA-funded research provides evidence that the spin axis of the Moon shifted by about five degrees roughly three billion years ago. The evidence of this motion is recorded in the distribution of ancient lunar ice, evidence of delivery of water to the early solar system. “The same face of the Moon has not always pointed towards Earth,” said Matthew Siegler of the Planetary Science Institute in Tucson, Arizona, lead author of a paper in today’s journal Nature. “As the axis moved, so did the face of the “Man in the Moon.” He sort of turned his nose up at...

1. Introduction As related by Clube and Napier in their monograph The Cosmic Winter, see [1], in the year 1178 A.D. four wise men of Canterbury were sitting outside on a clear and calm 18th June night, a half Moon standing placidly in the starry sky. Suddenly they noticed a flame jutting out of a horn of the Moon. Then they saw the Moon tremble and its colour change slowly from light brilliant to a darker reddish tone. Such a colour remained for all the time the Moon was visible during that phase. This story is found in a manuscript...

A team from Harvard University presented a study this month that remnants from an ancient Earth exists, right now, inside contemporary Earth. The group believes that their comparisons of isotopic ratios of noble gases from materials deep inside Earth with those near the surface provide testimony that the deep-down material is actually from the Earth that existed before its massive collision with another planet. That immense impact – the largest in geologic history – is what many believe led to creation of the Moon. The currently favored theory about how the Moon originated says that it was formed 4.5 billion...

Creation stories tend to be outlandish, in keeping with the near impossibility of explaining why the world is the way it is — from the week-long labours of the Old Testament God, to the eternal cycles of the Hindu creator Brahma, to Raven’s metaphysical trickery in Pacific Northwest First Nations tradition. Fanciful as they are, however, these myths have nothing on modern science, whose creation story — which already involves a mysterious Big Bang, perhaps one of many creations ex nihilo in infinite succession — this week got even weirder. At a geophysics conference in California, a series of discoveries...

A new analysis of lunar rocks brought home by Apollo mission astronauts has shed fresh light on the violent birth of the moon. Researchers in Germany have found small but distinctive chemical signatures that suggest the moon formed when a giant planetary body slammed into the early Earth 4.5bn years ago. Scientists have several theories for how the moon may have formed, but the "giant impact hypothesis" has been the leading explanation for some time. A cataclysmic impact between the Earth and a Mars-sized planet, known as Theia, would have scattered rock and dust from both bodies out into space,...