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Category: space – Page 384

If you thought space already had its fair share of terrifying places, think again. We’ve discovered scorching hot planets, inhospitable gas giants with winds faster than 500 miles an hour, and blackholes themselves, but these celestial objects have characteristics.

Imagine a place that’s literally just a void, a gap in space that has absolutely nothing and stretches millions of lightyears. Scientists have found such a gap and it defies all logic, but do we know anything about this gap? Or are these questions going to be unanswered?

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Using data collected over two decades ago, scientists from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, have compiled the first complete map of hydrogen abundances on the Moon’s surface. The map identifies two types of lunar materials containing enhanced hydrogen and corroborates previous ideas about lunar hydrogen and water, including findings that water likely played a role in the Moon’s original magma-ocean formation and solidification.

APL’s David Lawrence, Patrick Peplowski and Jack Wilson, along with Rick Elphic from NASA Ames Research Center, used orbital data from the Lunar Prospector mission to build their map. The probe, which was deployed by NASA in 1998, orbited the Moon for a year and a half and sent back the first direct evidence of enhanced at the lunar poles, before impacting the .

When a star explodes, it releases , or high-energy protons and neutrons that move through space at nearly the speed of light. When those cosmic rays come into contact with the surface of a planet, or a moon, they break apart atoms located on those bodies, sending protons and neutrons flying. Scientists are able to identify an element and determine where and how much of it exists by studying the motion of those protons and neutrons.

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Current approaches to de novo design of proteins harboring a desired binding or catalytic motif require pre-specification of an overall fold or secondary structure composition, and hence considerable trial and error can be required to identify protein structures capable of scaffolding an arbitrary functional site. Here we describe two complementary approaches to the general functional site design problem that employ the RosettaFold and AlphaFold neural networks which map input sequences to predicted structures. In the first “constrained hallucination” approach, we carry out gradient descent in sequence space to optimize a loss function which simultaneously rewards recapitulation of the desired functional site and the ideality of the surrounding scaffold, supplemented with problem-specific interaction terms, to design candidate immunogens presenting epitopes recognized by neutralizing antibodies, receptor traps for escape-resistant viral inhibition, metalloproteins and enzymes, and target binding proteins with designed interfaces expanding around known binding motifs. In the second “missing information recovery” approach, we start from the desired functional site and jointly fill in the missing sequence and structure information needed to complete the protein in a single forward pass through an updated RoseTTAFold trained to recover sequence from structure in addition to structure from sequence. We show that the two approaches have considerable synergy, and AlphaFold2 structure prediction calculations suggest that the approaches can accurately generate proteins containing a very wide array of functional sites.

The authors have declared no competing interest.

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When asteroid 2019 OK suddenly appeared barreling toward Earth on July 25, 2019, Luisa Fernanda Zambrano-Marin and the team of astronomers at the Arecibo Observatory in Puerto Rico quickly sprang into action.

After receiving an alert, the radar scientists zoned in on the asteroid, which was approaching from Earth’s blind spot — solar opposition. Zambrano-Marin and the team had just 30 minutes to collect as many radar readings as they could. The asteroid was traveling so fast, that’s all the time she’d have it in Arecibo’s sights. University of Central Florida (UCF) manages the Arecibo Observatory for the U.S. National Science Foundation under a cooperative agreement.

Because the asteroid appeared to come out of nowhere and was traveling so fast, it made headline news.

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Just days after the first formal release of its first show-off images scientists using the new James Webb Space Telescope (JWST) have posted some stunning new images of two spiral galaxies.

Posted on Flickr by Judy Schmidt working on the PHANGS Survey, the stunning image, above, shows the spectacular “Phantom Galaxy” (also called M74 and NGC 628), with others (scroll down) showing another spiral galaxy called NGC 7496.

The incredible new images are testament to Webb’s skill at seeing in infrared and thus seeing through the gas and dust that obscures a lot of what is going on in some of the most arresting objects in the night sky.

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Metamaterial Space Applications:

In this presentation I will talk about nanophotonics, more specifically metasurfaces – subwavelength patterned surfaces – and explain how this can be used for space applications. As recently displayed by the stunning images from the James Webb space telescope, we often rely on recording the intensity of light (e.g. with a camera) to study the universe. However, light fundamentally has several additional degrees of freedom which can carry information, e.g. polarization, phase, and spectral content. While it is true that many conventional optical components can address these degrees of freedom individually (e.g., polarizers, phase retarders, and filters), metasurfaces enable general manipulations of phase, amplitude, and polarization on the nanoscale, thereby providing ample opportunity to create new versions of existing components and even enable functionality not possible using conventional technologies. In the presentation I will cover several examples of metasurfaces I have been working on and explain their relevance for space applications. I will attempt to explain the working principles, why metasurfaces can be useful, as well as how we fabricate metasurfaces in a cleanroom.

About the speaker: Dr. Tobias Wenger is a postdoc at JPL’s microdevices laboratory (MDL) where his main efforts relate to nanophotonics — light at the nanoscale – and how we can engineer structures and components in order to control light in new ways. Tobias received his PhD from Chalmers University of Technology, Sweden, where he worked on understanding the physical properties of plasmons in graphene.

At JPL, Tobias is applying his knowledge of subwavelength electromagnetics to design metasurface-based optical components, mainly for infrared wavelengths. Metasurfaces are a novel approach to optics which uses subwavelength elements for controlling the phase, amplitude and polarization of transmitted and/or reflected electromagnetic radiation. Tobias research interests intersect optics, computational electromagnetics, and microfabrication and he enjoys both the practical and theoretical aspects of this work. During his postdoc time at MDL, he has worked on metasurface-based optical concentrators, IR detectors, plasmonic filters, wavefront sensing, and grating replication.

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Astronomers hope to explain how galaxies like this one can grow magnetic fields that stretch for thousands of light-years — and what affect they have on galactic evolution.

The finding came out of a project to study radio signals from spiral galaxies that are tilted so we see them edge-on from Earth’s point of view. For these galaxies, astronomers can more easily separate what’s happening outside of the galaxies’ disks, in the gas-filled “haloes” that surround them.

Using observations from a radio telescope in New Mexico called the Very Large Array, the astronomers measured properties of the radio emission coming from the halo of the galaxy NGC 4631. They’d known from past observations that there were large-scale magnetic fields that extended out of the disk into the halo of this galaxy.

But with the new data, they could see the directions these fields pointed across multiple dimensions. Their measurements revealed that the fields pointed alternately in and out of the galaxy’s disk along the flat view of the sky from Earth’s point of view. Another measurement showed that the fields also alternated in pointing toward and away from Earth along our line of sight to the galaxy.

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