Researchers have found that a light-sensitive protein in birds' retinas allows them to detect magnetic fields.

Protein in Birds' Eyes Helps Them 'See' Earth's Magnetic Field

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 Researchers have discovered a protein in birds’ eyes that allows them to see magnetic fields.
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 The protein, called Cry4, belongs to a group of proteins known to regulate circadian rhythms, or biological sleep cycles. It turns out that Cry4 serves a previously unknown function, interacting with light to help birds sense magnetic fields.
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<p>
 Here’s Dan Garisto, reporting for Science News:
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<p>
 If the researchers are correct, this would be the first time a specific molecule responsible for the detection of magnetic fields has been identified in animals.
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 “This is an exciting advance—we need more papers like these,” says Peter Hore, a chemist at the University of Oxford who has studied chemical reactions involved in bird navigation.
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 One study involving zebra finches analyzed Cry4 along with the proteins Cry1 and Cry2. The team found that Cry4, unlike Cry1 and Cr2, was produced steadily throughout the day. The researchers pointed out that birds may need to navigate their environment any time of night or day.
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 Another study, this one on European robins, demonstrated that Cry4 levels were consistent throughout a 24-hour cycle. What’s more, levels increased during the robins’ migratory season, when the birds would need to rely on their navigation skills the most. The team also noted that the location of Cry4 in the retina, an ideal location for an internal compass, provides it with access to a lot of light.
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 Prior to these studies, scientists thought that birds detected magnetic fields using the iron-rich cells in their beaks. Though the current research isn’t conclusive, it suggests that previous beliefs about avian compasses may have misguided.
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<p>
 Photo credit:
 <a href="https://en.wikipedia.org/wiki/European_robin#/media/File:Erithacus_rubecula_with_cocked_head.jpg">
  Francis C. Franklin / Wikimedia Commons (CC-BY-SA-3.0)
 </a>
</p>

<p>Called Cry4, the protein belongs to a group known to regulate circadian rhythms, or biological sleep cycles.</p>

Unprecedented Fossil Provides New Understanding of Bird Evolution

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 Paleontologists have just uncovered the remarkably pristine cranium of an ancient bird along with three partial skulls. These remains combine modern and primitive features in surprising ways to capture a fascinating moment in avian evolution.
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 The Ichthyornis fossils starkly contrast the skeletons of current birds. Modern birds have less musculature in their jaw and larger braincases than their predecessors. Whereas today’s birds have lightweight, toothless snouts, the fossils have large, toothed upper jaws—more comparable to those of dinosaurs. The Ichthyornis specimens even have openings in the top of their skulls, just like in T. rex fossils, to allow for large muscles.
</p>
<p>
 Here’s John Pickrell, reporting for National Geographic:
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<blockquote>
<p>
 “That is a very surprising observation that we would never have expected to make in an animal as closely related to modern bird as Ichthyornis,” [says study leader Daniel Field of the University of Bath in the U.K.] “The new fossils show a surprisingly late retention of a dinosaur-like architecture of the roof of the skull.”
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 “Bird skulls are at a real premium among paleontologists, as they don’t get preserved in most circumstances,” [Field says]
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 Paleontologists have been waiting for a discovery like this for decades. Though fossil–hunters have been uncovering Ichthyornis remains since the 1870s, these fossils have usually been compressed almost flat. The new find has finally allowed researchers to create a 3-D model of these skulls in their original shapes.
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 Some of the fossils are still lodged in rocks, but that hasn’t deterred paleontologists. They CT-scanned the skulls and put together the data they gathered from all of the different fossils to produce a 3-D digital reconstruction.
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 The researchers hope that this discovery is only the beginning. Though ancient bird skulls are notoriously difficult to find, they’re optimistic that their success will encourage others to continue the search and take up the shovel.
</p>
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<p>
 Paleontologists have been waiting for a discovery like this for decades. Though fossil–hunters have been uncovering Ichthyornis remains since the 1870s, these fossils have usually been compressed almost flat. The new find has finally allowed researchers to create a 3-D model of these skulls in their original shapes.
</p>
<p>
 Some of the fossils are still lodged in rocks, but that hasn’t deterred paleontologists. They CT-scanned the skulls and put together the data they gathered from all of the different fossils to produce a 3-D digital reconstruction.
</p>
<p>
 The researchers hope that this discovery is only the beginning. Though ancient bird skulls are notoriously difficult to find, they’re optimistic that their success will encourage others to continue the search and take up the shovel.
</p>
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<p>
 Photo credit:
 <a href="https://www.nature.com/articles/s41586-018-0053-y">
  Daniel J. Field / Nature
 </a>
</p>

<p>A remarkably intact skull from the dinosaur-era bird is giving paleontologists valuable insights into avian history.</p>

Map Of One Billion Stars Could Revolutionize Our Understanding of Space

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  A newly-released data set from the European Space Agency’s Gaia mission contains high-precision measurements about the distances and movements of around 1.4 billion stars, providing unparalleled information about our galaxy and beyond.
 </p>
<p>
  This is the second set of data we’ve received from Gaia, a spacecraft orbiting the Sun. The vehicle launched in 2013 and released its first batch of measurements three years later. The new data set goes far beyond the 2016 catalogue by mapping a dizzying number of stars in astonishing detail—and even measuring the brightness, color, and surface temperatures of some stars.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/gaia_1024x576.width-990_OefPLi8.jpg"/>
<figcaption>The European spacecraft Gaia just unveiled this portrait of the Milky Way galaxy.
        
    </figcaption>
</figure>
<p>
  Jackie Faherty, an astronomer at the American Museum of Natural History, says the importance of this map cannot be overestimated. “Gaia is revolutionary. There’s not a single aspect of what you study that can’t be touched by this mission—anything from the closest-by things that I study to the farthest things in the universe.”
 </p>
<p>
  To put things in perspective, Faherty previously spent three years measuring the distances to 75 celestial objects called brown dwarf stars. “These measurements are hard to make,” she explains.
 </p>
<p>
  Yesterday, American astronomers gathered in the wee hours of the morning in anticipation of the European Space Agency’s press release and the subsequent data drop. Faherty was watching at the Flatiron Institute in New York City with her colleagues. The room was overflowing with astronomers, and as soon as the data was online, everyone rushed to hackathons where they excitedly began digging into the science.
 </p>
<p>
  Scientists will need years and years to analyze all the data. And this is only the beginning—a third release in 2020 will provide even more data, this time about planets outside our solar system.
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  Gaia will be the first to use a novel technique called astrometric detection to look for small wobbles in stars’ positions. Since planets exert a gravitational pull on the stars that they orbit, these wobbles can provide valuable information about planets in the far corners of our universe.
 </p>
<p>
  The 2020 data release will complement NASA’s Kepler mission and its successor
  <a href="http://www.pbs.org/wgbh/nova/next/space/nasas-tess-spacecraft-will-scan-the-sky-for-exoplanets/">
   TESS
  </a>
  , which
  <a href="https://www.facebook.com/NOVApbs/videos/10155418021112196/">
   finds planets
  </a>
  using transit photometry and detects the subtle dimming of stars as planets pass between Earth and these stars. The hope is that Gaia will verify NASA’s findings and further our search for new planets and life beyond Earth.
 </p>
<p>
  The best part is that this bounty of data isn’t just for astronomers. Anyone with an internet connection can download Gaia’s measurements from the
  <a href="http://gea.esac.esa.int/archive/">
   project website
  </a>
  and figure out where their favorite space object is.
 </p>
<p>
  “To me, that’s the most important thing that you could get across. Let people know that it’s their data, as much as it’s our data,” Faherty said.
 </p>
</section>
<p>
 Image credit: ESA / Gaia / DPAC
</p>

Diamonds In Meteorite May Come From ‘Lost’ Planet

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  A meteorite with unusual composition may provide valuable insights into the early history of our solar system.
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  The meteorite, first discovered in 2008, belongs to a rare category of space rocks called ureilites. Compared to other meteorites, these contain a large amount of graphite and diamond.
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  An analysis of this particular meteorite’s diamonds revealed that they are full of inclusions, or tiny imperfections, that provide clues about the gems’ origins.
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/diamonds_1024x576.width-990_9I1lnWz.jpg"/>
<figcaption>A transmission electron microscopy image of one of the diamonds recovered from the meteorite
        
    </figcaption>
</figure>
<p>
  Here’s Nicholas St. Fleur, reporting for
  <em>
   The New York Times
  </em>
  :
 </p>
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<p>
   “What for a jeweler is an imperfection becomes for me something that is very useful because it tells me about the history of the diamond,” said Dr. Gillet, [an author of the
   <a href="https://www.nature.com/articles/s41467-018-03808-6">
    paper
   </a>
   that was published in Nature Communications]. “It has a chemistry which has no equivalent in the solar system today, in terms of planets,” he said.
  </p>
</blockquote>
<p>
  The unique composition of the meteorite suggests that it is about 4.5 billion years old and hails from a time when protoplanets, or planets in their early stages of evolution, orbited our sun. These protoplanets collided with one another to form the planets of our current solar system.
 </p>
<p>
  Dr. Gilbert and his team believe that the meteorite traces its origins back to when a protoplanet collided with another planet. The collision produced debris that remained in space for billions of years before falling to Earth.
 </p>
<p>
  The rock’s special chemistry isn’t the only reason scientists are excited. It also contains the largest meteorite diamonds ever discovered.
 </p>
<p>
  The authors of the paper pointed out that diamonds of this size and composition could only be created under extreme pressure. They concluded that the diamonds formed under 20 giga-pascals, about 200,000 greater than atmospheric pressure at sea level.
 </p>
<p>
  These conditions could only be achieved inside a planet the size of Mercury or Mars, providing more evidence that the meteorite comes from a ‘lost’ planet.
 </p>
</section>
<p>
 Photo credit: Dr. F. Nabiei/Dr. E. Oveisi, EPFL, Switzerland
</p>

AI Lets Scientists See Through Cell Membranes

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 We’ve been spying on our body’s cells for centuries using microscopes, but peering inside them has been more of a challenge. But now, artificial intelligence is helping researchers visualize the inner workings of living cells.
</p>
<p>
 Scientists created the model by programming a computer to study thousands upon thousands of images from living cells. The computer eventually figured out the internal organization of a cell based on simple images.
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<p>
 The 3D model overcomes the limitations of existing technologies such as microscopes by allowing scientists to observe all of the components of a cell at the same time, offering an unprecedented opportunity to study their interactions. The model also offers advantages over techniques that use dyes, intense light, or genetic modifications, since these methods damage the cells under observation.
</p>
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<p>
 Here’s Jon Hamilton, reporting for NPR:
</p>
<blockquote>
<p>
 Until now, there haven’t been good alternatives, says Graham Johnson, a computational biologist and medical illustrator at the Allen Institute.
</p>
<p>
 He recalls the frustration when he was in high school and college of trying to study cells with a conventional microscope.
</p>
<p>
 “You’d see a black-and-white clear object and it had lots of smaller objects inside of it that were moving around and changing shape and doing all sorts of mysterious things,” Graham Johnson says. But there was no good way to identify those shapes or understand what they were doing.
</p>
<p>
 What’s more, this model is freely available. Where current techniques for studying cells require costly, specialized equipment, the new model can use inexpensive, commonly available hardware.
</p>
</blockquote>
<p>
 Roger Brent, a researcher from the Fred Hutchinson Cancer Research Center in Seattle who didn’t participate in the project, has already used the technology in his own research on yeast cells and managed to successfully run the model using off-the-shelf computer parts.
</p>
<p>
 Researchers are optimistic that the model will help scientists better understand diseases, facilitating comparisons of healthy and unhealthy cells. The hope is that even labs with little equipment could use the model to see inside cancer cells and analyze the effectiveness of different treatments.
</p>
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<p>
 Image credit: Allen Institute
</p>

<p>Current techniques for visualizing cells are limited, costly, and damaging to the very cells being studied. A new model hopes to change that.</p>

A computer-generated image of objects in Earth orbit that are currently being tracked

New Experiment Will Attempt to Clean Up Space Junk

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<p>
 Looking up at the night sky, it’s easy to think of space as a barren wasteland. But over 7,500 tons of space junk—from old spacecraft to flecks of paint—looms above our heads, in orbit around the Earth.
</p>
<p>
 These pieces of debris present collision risks to operational missions. The RemoveDebris satellite project hopes to test multiple approaches for dealing with these hazards—such as capturing objects in a net and ensnaring them with a small harpoon.
</p>
<p>
 Here’s Jonathan Amos, reporting for the BBC:
</p>
<blockquote>
<p>
 Its principal investigator is Prof Guglielmo Aglietti. He said the jury was still out on the best way to capture and remove space junk.
</p>
<p>
 “As you know, there are other people who are going with the idea of a robotic arm. All these different technologies have their advantages and disadvantages,” he told BBC News.
</p>
<p>
 The net and harpoon technology being tested are sometimes risker than a robotic arm. However, it is challenging to capture spinning space junk with a robotic arm, and a net could be more effective at targeting whirling debris.
</p>
<p>
 Mission leaders emphasize the low costs of their net and harpoon, stating that future efforts to clean up space junk will probably be limited by cost.
</p>
</blockquote>
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<p>
 The current UK-led mission is receiving half of its funding from the European Commission and half from 10 partners. These include Airbus and the Houston-based NanoRacks, a private company that serves customers such as NASA and the European Space Agency.
</p>
<p>
 The experiment is slated to begin in late May. Until then, the satellite will be stored at the International Space Station.
</p>
<p>
 Once the mission is over, RemoveDebris will activate a large membrane “sail” to pull the satellite down to Earth so that it does not contribute to space debris itself.
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<p>
 Image credit: NASA
</p>

<p>Over 7,500 tons of space junk—from old spacecraft to flecks of paint—looms above our heads.</p>

Yasmeen Fakhro