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Blog – Page 8729

Circa 2016

Laser physicists in Munich have measured a photoionization — in which an electron exits a helium atom after excitation by light — for the first time with zeptosecond precision. A zeptosecond is a trillionth of a billionth of a second (10^−21 seconds). This is the greatest accuracy of time determination ever achieved, as well as the first absolute determination of the timescale of photoionization.

If light hits the two electrons of a helium atom, one must be incredibly fast to observe what occurs. Besides the ultra-short periods in which changes take place, quantum mechanics also comes into play. Laser physicists at the Max Planck Institute of Quantum Optics (MPQ), the Technical University of Munich (TUM) and the Ludwig Maximilians University (LMU) Munich have now measured such an event for the first time with zeptosecond precision.

Either the entire energy of a light particle (photon) can be absorbed by one of the electrons or a division can take place, if a photon hits the two electrons of a helium atom. Regardless of the energy transfer, one electron leaves the atom. This process is called photoemission, or photoelectric effect, and was explained by Albert Einstein at the beginning of last century.

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In 1884, a schoolmaster and theologian named Edwin Abbott wrote a novella called Flatland, which tells the story of a world populated by sentient two-dimensional shapes. While intended as a satire of rigid Victorian social norms, Flatland has long fascinated mathematicians and physicists and served as the setting for many a thought experiment.

One such thought experiment: How can be controlled in two dimensions?

When a wave of light is confined on a two-dimensional plane by certain materials, it becomes something known as a —a particle that blurs the distinction between light and matter. Polaritons have exciting implications for the future of optical circuits because, unlike electronic integrated circuits, integrated optics is difficult to miniaturize with commonly used materials. Polaritons allow light to be tightly confined to the nanoscale, even potentially to the thickness of a few atoms.

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Samples of lunar dust and rock returned to Earth during the Apollo missions quickly offered scientists new insights into the makeup of our Moon, but what do they look like under the microscopes of today? NASA has just cracked open the first of two untouched lunar samples for study with modern scientific instruments, with one eye on the upcoming Artemis missions that will return humans to the Moon in 2024.

This NASA initiative is known as the Apollo Next-Generation Sample Analysis project. It concerns two samples collected in the early 1970s that were quickly sealed and stored in the form of tubes of rock and soil, representing two-feet of vertical layering from the lunar surface.

“We are able to make measurements today that were just not possible during the years of the Apollo program,” says Dr. Sarah Noble, ANGSA program scientist at NASA Headquarters in Washington. “The analysis of these samples will maximize the science return from Apollo, as well as enable a new generation of scientists and curators to refine their techniques and help prepare future explorers for lunar missions anticipated in the 2020s and beyond.”

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The Paul G. Allen Frontiers Group, a division of Seattle’s Allen Institute, is making a total of $7.5 million in awards to its latest class of five biomedical researchers.

The themes for this year’s Allen Distinguished Investigators focus on stem cell therapies and single-cell interactions in their native environments.

“The field of stem cell biology has the potential to change how we treat diseases by helping precision medicine, and there’s so much we still don’t understand about the interplay between cells in living tissues or organs,” Kathy Richmond, director of the Frontiers Group, said today in a news release.

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A species of worm that can infect human eyes has done it again, and this time it chose a 68-year-old woman from Nebraska. The woman is thought to be only the second human victim of these worms ever documented. But the incident signals they could become an emerging parasitic disease in the U.S.

The disturbing details of the case were laid out in a paper published this October in the journal Clinical Infectious Diseases. The woman’s doctors, as well as researchers from the Centers for Disease Control and Prevention, contributed to the paper.

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Scientists analyzing data from a defunct satellite say we should all consider that our universe might be round, rather than flat. The consequences, they explain in a new paper, could be crisis-inducing.

Current theories of the universe, which describe its age, size, and how it evolves over time, are built around a flat spacetime. A new paper reiterates that data from the final Planck satellite release might be better explained by a round universe than a flat universe. Though not everyone agrees with the paper’s conclusions, the authors write that the consequences of assuming a flat universe when the universe is actually round could be dire.

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