The virtually identical oxygen isotope compositions of the Earth and Moon revealed by Apollo return samples have been a challenging constraint for lunar formation models. For a giant impact scenario to explain this observation, either the precursors to the Earth and Moon had identical oxygen isotope values or extensive homogenization of the two bodies occurred following the impact event. Here we present high-precision oxygen isotope analyses of a range of lunar lithologies and show that the Earth and Moon in fact have distinctly different oxygen isotope compositions. Oxygen isotope values of lunar samples correlate with lithology, and we propose that the differences can be explained by mixing between isotopically light vapour, generated by the impact, and the outermost portion of the early lunar magma ocean. Our data suggest that samples derived from the deep lunar mantle, which are isotopically heavy compared to Earth, have isotopic compositions that are most representative of the proto-lunar impactor ‘Theia’. Our findings imply that the distinct oxygen isotope compositions of Theia and Earth were not completely homogenized by the Moon-forming impact, thus providing quantitative evidence that Theia could have formed farther from the Sun than did Earth.
Category: space – Page 716
Astronomers scouring the cosmos for new planets have made a chance discovery, identifying the rare eclipse of two brown dwarfs.
“This is a great example of scientific serendipity,” Adam Burgasser, a co-leading author on this study and a professor of physics at UC San Diego, said in a statement. “While searching for planets, we found an eclipsing brown dwarf binary, a system that is uniquely suited for studying the fundamental physics of these faint celestial objects.”
Using data from the Hubble Space Telescope’s Cosmic Origins Spectrograph, the team was able to observe the distinctive absorption signature in the spectrum of light that passes through it, and the sight-lines of hundreds of distant quasars that pierce the volume of space occupied by the SDSS galaxies, says the university.
This lowly slime mold does a good job of characterizing the large-scale structure of the Universe over a wide range of scale, Burchett told me.
“I see how it works from a mathematical and [topological] perspective, but that doesn’t diminish my continued amazement that the slime mold-inspired method handles this difficult problem so elegantly and efficiently,” Burchett told me.
This new star only appears to be pulsating in one hemisphere of its surface.
“We’ve known theoretically that stars like this should exist since the 1980s,” said Don Kurtz, study co-author and inaugural Hunstead Distinguished Visitor at the University of Sydney from the University of Central Lancashire in Britain. “I’ve been looking for a star like this for nearly 40 years and now we have finally found one.”
Happy #InternationalWomensDay! As of March 2020, 65 women have flown in space. Of these, 38 have worked aboard the International Space Station as long-duration crew members. Women have contributed to construction of station, served as shuttle pilots and commanders, commanded station expeditions and participated in numerous spacewalks including the recent series of all-woman excursions. Women currently hold the record for the single longest spaceflight by an American and the record for cumulative spaceflight time by an American. Their ongoing achievements will contribute to NASA successfully landing the first woman and the next man on the Moon as part of the Artemis program.
But using porous TCP to print bones does have some drawbacks. Its compressive strength is much lower than that of some human load-bearing bones, such as our thighbones. Compressive strength would rise over time, but it could be years before it would match pre-operation strength levels.
3D Printing Bones for Mars?
Several other groups are working on similar approaches. At NYU School of Medicine and NYU Langone Health, scientists have been developing 3D printed scaffold implants that could help patient groups such as children with skull deform ities. Early research results show that up to 77 percent of the bone scaffolding had been absorbed and replaced by natural bone 6 months after surgery, and that the newly-grown bone was just as strong as the original.
Why does the cosmic microwave background have a strange patch that is much colder than expected? Syed Faisal ur Rahman looks at some possible explanations.
Teleportation is no longer science fiction, says a team of Chinese scientists, after teleporting a photon particle from the Earth’s surface to an orbiting satellite 870 miles (1,400 km) away. This does not mean, however, that we are now able to beam people up and down like Star Trek’s captains James Kirk, Jean-Luc Picard, or Kathryn Janeway – that is still very much in the realm of science fiction, physicists say.
Teleportation, also known as teletransportation, is the theoretical transfer of energy or matter from one point to another instantly – without traveling through the physical space between them.
For all of science’s impressive advancements, one problem has stubbornly eluded us: Why do we have consciousness? How does inert unconscious matter give rise to the light of conscious experience? Neuroscientist Donald Hoffman has been pondering this question throughout his career. His thinking has gradually led him to a surprising possibility — that consciousness itself is fundamental to reality. Donald’s theory, however, differs from that of the growing number of other scientists and philosophers now arriving at this conclusion.
“We’ve been stuck on the same problem for centuries. It’s time to take a different approach.”
The fundamental nature of reality, Donald theorizes, is comprised of an infinite network of interacting conscious agents. Uniquely, Donald offers a precise mathematical definition of a conscious agent. He believes the theory may be used to reconstruct the universe and existing scientific discoveries purely through the interaction of these units of consciousness.