WASHINGTON-The stark difference between the Moon's heavily-cratered farside and the lower-lying open basins of the Earth-facing nearside has puzzled scientists for decades.

Now, new evidence about the Moon's crust suggests the differences were caused by a wayward dwarf planet colliding with the Moon in the early history of the solar system. A report on the new research has been published in AGU's Journal of Geophysical Research: Planets.

The mystery of the Moon's two faces began in the Apollo era when the first views of its farside revealed the surprising differences. Measurements made by the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012 filled in more details about the structure of the Moon - including how its crust is thicker and includes an extra layer of material on its farside.

There are a number of ideas that have been used to try and explain the Moon's asymmetry. One is that there were once two moons orbiting Earth and they merged in the very early days of the Moon's formation. Another idea is that a large body, perhaps a young dwarf planet, found itself in an orbit around the Sun that put it on a collision course with the Moon. This latter giant impact idea would have happened somewhat later than a merging-moons scenario and after the Moon had formed a solid crust, said Meng Hua Zhu of the Space Science Institute at Macau University of Science and Technology and lead author of the new study. Signs of such an impact should be visible in the structure of the lunar crust today.

"The detailed gravity data obtained by GRAIL has given new insight into the structure of the lunar crust underneath the surface," Zhu said.

The new kilogram has finally arrived.

Updates to scientists' system of measurement went into force May 20, redefining the kilogram and several other units in the metric system. The revamp does away with some outdated standards - most notably, a metal cylinder kept in a vault near Paris that has defined the kilogram for 130 years (SN: 12/8/18, p. 7).

Tinkering with units allows scientists to more precisely measure weights, temperatures, electric currents and other quantities laid out in the International System of Units used around the globe. The kilogram, the basic unit of mass, is now defined by a quantum quantity known as the Planck constant. That value, an immutable constant of nature, is the same everywhere in space and time. That's an improvement over the Parisian artifact, which could have changed slightly if gunk or scratches marred its surface.

Also redefined, according to an agreement reached in November 2018 at the 26th General Conference on Weights and Measures in Versailles, France, are the kelvin, the unit of temperature; the ampere, the unit of electric current; and the mole, the unit for an amount of substance (SN: 12/8/18, p. 7).

Scientists now have their sights set on updating the unit of time: the second.

The chemical composition of the Earth's mantle is a lot more variable and diverse than previously thought, a new study has revealed.

According to a new analysis of cores drilled through the ocean crust, the mantle is made up of distinct sections of rock each with different chemical make-ups.

The chemical composition of the mantle has been notoriously difficult to determine with a high degree of certainty because it is largely inaccessible.

Scientists have traditionally relied on lava that erupts on the ocean floor to give them some idea of what the mantle is made up of, and so far studies have suggested that it's chemically mostly the same everywhere on the planet.

However in their new study, published in Nature Geoscience, the team of researchers led by scientists at Cardiff University have studied the very first minerals that begin to form when lava first makes contact with the crust at mid-ocean ridges.

The abortion debate is once again taking center stage in US politics, and the prospect of artificial wombs is slowly becoming a part of the conversation, as the technology is actually starting to become a reality. According to some experts in the field, we are just a decade away from this type of technology reaching the public.

Dr. Carlo Bulletti, associate professor at Yale University's obstetrics, gynecology, and reproductive science department, has predicted that a fully functioning artificial womb could be used in the medical field in the next ten years.

Scientists call this Ectogenesis, which is an artificial pregnancy outside of the body. Numerous experiments have tested this process with animals and have been slowly advancing the success rates of the procedure. In the most notable of these experiments, a premature lamb was kept alive for weeks in an artificial womb.

There are still concerns about how a pregnancy like this would impact the health and mental development of the baby, considering the importance of bonding, but many experts insist that artificial births are the future.

In a recent interview with Metro, Dr. Anna Smajdor, associate professor of practical philosophy at the University of Oslo, explained that bonding can happen mentally, but did not address whether or not this could cause developmental issues for the baby.

The far side of the moon is weirder than we previously thought and new research indicates that, in the distant past, the moon could have faced off against an unknown object in a massive collision that changed its face.

On the near side that faces Earth, we can see large dark areas of volcanic basalt dotting the lunar landscape. Meanwhile, on the dark side, thanks to the Soviet probe Luna 3 which orbited the Moon in 1959, we know that the surface is riddled with thousands upon thousands of craters.

While many might posit that the Earth has simply protected the near side from aeons of meteorite impacts, new research suggests that the real answer may not be so simple (the Earth is too far from the moon to provide enough anti-meteor defense anyway).

Analysis of data from 2012 reveals that the dark side of the moon has an extra-thick crust (some 20km or 12.5 miles deep) which contains a 10km thick layer of magnesium and iron enriched material not found on the near side.

Previous theories suggested our moon may actually have been formed when two smaller moons merged.

For 130 years, a cylinder made of a platinum-iridium alloy and stored in a suburb of Paris called Saint Cloud has been the official definition of a kilogram, the internationally accepted basic unit of mass. But that will change once and for all on May 20, when for the first time all of the basic units of measurement will be officially defined in terms of atomic properties and fundamental physics constants, rather than specific, human-made objects.

The other objects on which physical standards are based, such as the standard meter, were already replaced years ago, but the kilogram - generally known as the kilo for short - turned out to be a harder unit to define in absolute terms. Physicists and engineers have been frustrated, however, by the inevitable imprecision of a unit based on a single physical object.

Despite the greatest of precautions, every time the standard kilo was handled - for example, to compare it to another unit that could then be used to calibrate instruments - it would shed some atoms and its mass would be slightly changed. Over its lifetime, that standard kilo is estimated to have lost about 50 micrograms. A better way was needed.

Now, instead of a particular lump of metal in a single location, a kilo is to be defined by fixing the numerical value of a fundamental constant of nature known as the Planck constant. This constant relates the energy of a photon to its frequency, and is referred to by the letter h. It is now defined as 6.62607015 times 10^-34 kilograms times square meters per second, thereby defining the kilogram in terms of the second and the meter. Since the second and meter are already defined completely in terms of physical constants, the kilogram is now also defined only in terms of fundamental physical constants.

Some may find this new definition complicated and difficult to understand, but Wolfgang Ketterle, a Nobel Prize winner and the John D. MacArthur Professor of Physics at MIT, doesn't see it that way. "Conceptually, the definition is very simple," he says.

Ketterle notes that the new definition of a kilogram corresponds to the mass of an exact number of particles - a very large number of particles. According to his formulation, it is 1.4755214 times 10⁴⁰ photons (particles of light) of a particular wavelength, which is that of cesium atoms used in atomic clocks.

This finding from a team of researchers in Sweden and England sheds some light on how man's best friend came to be and found being a dog owner is may be genetic.

A study of twins found that getting a dog is influenced by an individual's genes and may even be inherited.

It is impossible to say which genes are involved from the study but identical twins agreed far more than non-identical pairs on whether they would have a pet pooch.

Previous research found if we had a pet as a child we are more likely to like animals and own a pet in adulthood.

Following the publication of Yale polymath David Gelernter's wonderful essay at The Claremont Review of Books, "Giving Up Darwin," we're seeing, yet again, two ways for Darwinists to approach the subject of intelligent design and Darwin skepticism. Both are pretty lame.

This week we had Razib Khan's article at National Review, urging that ID proponents aka "evolution deniers" not be engaged, out of deference to evolution's sparkling contribution to Western civilization. This from a self-described geneticist (actually he's a PhD candidate) who himself engaged for years with the racists of the alt-right and whose name still appears on the homepage of a website featuring Holocaust deniers. Khan doesn't mention Gelernter, but he does repeatedly refer to Michael Behe and his (unnamed) recent book, Darwin Devolves. True to his own advice, Khan opts not to indicate what the book argues, much less to argue against it.

Now here's Jerry Coyne, an actual evolutionary biologist but a bit of a comic figure as well. Typical reasoning from Coyne, who like Khan is an atheist: "Seriously, if God wants us to accept Him, why can't he just come down to Earth and do a few irrefutable miracles that can be witnessed, photographed, and so on?" That was from a response to Stephen Meyer, author of Darwin's Doubt, whom Gelernter acknowledges as an important influence, along with David Berlinski and a book I edited, Debating Darwin's Doubt.

The Willamette Meteorite weighs 15.5 tons. This iron meteorite, which was found in Oregon. It is the largest meteorite found in North America The Willamette Meteorite is an iron-nickel meteorite discovered in the U.S. state of Oregon. It is the largest meteorite found in North America and the sixth largest in the world.

There was no impact crater at the discovery site; researchers believe the meteorite landed in what is now Canada or Montana, and was transported as a glacial erratic to the Willamette Valley during the Missoula Floods at the end of the last Ice Age (~13,000 years ago).

The meteorite is currently on display at the American Museum of Natural History in New York City, which acquired it in 1906. Having been seen by an estimated 40 million people over the years, and given its striking appearance, it is among the most famous meteorites known.

CBET 4625 & MPEC 2019-J122, issued on 2019, May 12, announce the discovery of a comet (magnitude ~17.5) in the course of the "Mt. Lemmon Survey" (G96), in images taken on 2019, May 04 with a 1.5-m reflector + 10K CCD. This object was reported as a comet by R. A. Kowalskiand D. Rankin (G96, May 4). The new comet has been designated C/2019 J1 (Lemmon).

I performed follow-up measurements of this object while it was still on the PCCP webpage. Stacking of 12 unfiltered exposures, 120 seconds each, obtained remotely on 2019, May 06.4 from H06 (iTelescope network) through a 0.25-m f/3.4 reflector + CCD, shows that this object is a comet with a diffuse coma about 10 arcsec in diameter.

My confirmation image (click on it for a bigger version)