Shannon Hall

When SpaceX, the private rocket company founded by Elon Musk, launched the first batch of Starlink orbiters in May, many astronomers were surprised to see that the satellites were extremely bright, causing them to fear that the constellation would wreak havoc on scientific research and transform our view of the stars. Since then, many scientists have been on a mission to better quantify the impacts of Starlink and to share their concerns with SpaceX.

In response, SpaceX has said that it wants to mitigate the potential impacts of Starlink. But at the same time, the company is still moving full steam ahead.

In October, Musk announced that he was using Twitter via a Starlink internet connection, as his company was requesting permission from the Federal Communications Commission to operate as many as 30,000 satellites on top of the 12,000 already approved. Should SpaceX succeed in sending this many satellites to low Earth orbit, its constellation would contain more than eight times as many satellites as the total number currently in orbit.

That move added to the worries of many astronomers.

When James Lowenthal, an astronomer at Smith College, first saw the train of Starlink satellites marching like false stars across the night sky in the spring, he knew something had shifted.

“I felt as if life as an astronomer and a lover of the night sky would never be the same,” he said.

Most of the first Starlink nodes have since moved to higher orbits and are now invisible for most of us who live under bright city lights. But they are still noticeable from places with dark skies. If thousands more of these satellites are launched, Lowenthal said he feared “it will look as if the whole sky is crawling with stars.”

Since May, the American Astronomical Society has convened an ad hoc committee with Lowenthal and other experts to discuss their concerns with SpaceX representatives once a month.

At the same time, SpaceX has been working directly with the National Radio Astronomy Observatory, a federally funded research center that operates facilities across the world, to jointly minimize potential impacts of Starlink satellites on radio wavelengths that astronomers use.

But these conversations did not focus on light pollution, a problem presented by the reflective surfaces of proposed satellite constellations such as Starlink. At first, SpaceX said the complication would be minimal, and the new committee is trying to assess the impact and actively find solutions.

“So far, they’ve been quite open and generous with their data,” Lowenthal said. “But they have not made any promises.”

A spokeswoman from SpaceX said the company was taking steps to paint the Earth-facing bases of the satellites black to reduce their reflectiveness. But Anthony Tyson, an astronomer at the University of California, Davis, said that would not solve the problem.

Tyson is the chief scientist for the Large Synoptic Survey Telescope — a 27-foot, billion-dollar telescope under construction in Chile that will scan the entire sky every three days. The survey, the world’s largest yet, will help astronomers better understand dark energy, dark matter, the origin of the Milky Way and the outer regions of the solar system. But because it is designed to scan faint objects, it is expected to be greatly affected by the satellites.

Tyson’s simulations showed that the telescope would pick up Starlink-like objects even if they were darkened. And they wouldn’t just affect a single pixel in a photograph. When there is a single bright object in the image, it can create fainter artifacts as well because of internal reflections within the telescope’s detector. Moreover, whenever a satellite photobombs a long-exposure image, it causes a bright streak of light that can cross directly in front of an object astronomers wish to observe.

“It’s really a mess,” Tyson said.

Knowing how challenging it would be to correct these interrupted images, Tyson decided the best step forward was to set the telescope to avoid Starlink satellites. While simulations based on the earlier 12,000-satellite total suggested that would be possible, SpaceX’s application for 30,000 additional satellites upset the calculations.

“We’re redoing the models now just to see what’s visible at any one time — and it’s really quite frightening,” said Patrick Seitzer, a professor of astronomy emeritus at the University of Michigan, who has been running similar analyses to determine how many satellites will be visible and when.

His preliminary results suggest that avoiding the satellites would be difficult during twilight — a serious problem given that potentially hazardous asteroids and many objects in the solar system are best seen during this time. The satellites thus limit the ability of astronomers to observe them.

And Tyson’s early simulations also confirm the potential problems, demonstrating that over the course of a full year, the giant telescope would not be able to dodge these satellites 20% of the time. Instead, those images would be effectively ruined.

SpaceX’s 30,000 satellites might also just be the start as other companies, such as Amazon, Telesat and OneWeb, plan to launch similar mega-constellations.

“If there are lots and lots of bright moving objects in the sky, it tremendously complicates our job,” Lowenthal said. “It potentially threatens the science of astronomy itself.”

Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who closely tracks objects in orbit, agrees.

“There is a point at which it makes ground-based astronomy impossible to do,” he said. “I’m not saying Starlink is that point. But if you just don’t worry about it and go another 10 years with more and more mega-constellations, eventually you are going to come to a point where you can’t do astronomy anymore. And so let’s talk about it now.”

While astronomers are starting those conversations, they have little legal recourse. There are no regulations in place to protect the skies against light pollution.

“International space law is pretty wide open,” said Megan Donahue, an astronomer at Michigan State University and president of the American Astronomical Society. While many astronomers have been concerned about radio interference and space debris, she says light pollution is a bigger concern because there are no rules in place. That means any path forward relies on the goodwill of SpaceX and other companies.

“It’s more of a philosophical question,” Donahue said. “It kind of boils down to: How much do I trust corporate goodwill, and how much would a corporation care about the opinion of people who care about science and astronomy?”

This article originally appeared in

SpaceX Launches 60 Additional Starlink Satellites to Orbit

On Monday morning, SpaceX launched one of its reusable rockets from Cape Canaveral, Florida, carrying 60 satellites into space at once. It was the second payload of Starlink, its planned constellation of tens of thousands of orbiting transmitters to beam internet service across the globe.

The discovery, formally reported Wednesday in Nature,is a stark reminder that there is much more to be found in our own backyard, with implications for our understanding of worlds around other stars in our galaxy.

“I think people have the impression that we know everything there is to know about the moons of Jupiter, the moons of Saturn, the moons of Uranus and the moons of Neptune — but we don’t really,” said Anne Verbiscer, a planetary scientist at the University of Virginia, who was not involved in the recent discovery. “We haven’t found everything.”

That’s especially true for Uranus and Neptune, which are known as the ice giants. While every other planet in our solar system has been poked and prodded by multiple spacecraft, these two remain largely unexplored. Voyager 2 did swing past Neptune 30 years ago — shooting images that revealed rings, six new moons and its dynamic blue globe. But the spacecraft was moving too fast and was limited by technology designed in the 1970s.

“What this paper shows is that you couldn’t learn everything with that one flyby,” said Heidi Hammel, a planetary astronomer and executive vice president at the Association of Universities for Research in Astronomy (AURA) in Washington, D.C., who was not involved in the study.

Mark Showalter, a researcher at the SETI Institute in Mountain View, California, did not set out to make this discovery. He was analyzing Neptune’s rings with a new technique to process old images that essentially twisted them while adding them together. That allowed him to better see the rings, which are both faint and quick-moving.

On a whim, he decided to apply that same technique to other parts of the image he produced. To his surprise, a tiny white dot appeared. Further analyses have confirmed that it is a moon, and a rather odd one.

It’s both tiny (at roughly 20 miles in diameter, it’s nearly the north-to-south distance of Long Island) and its fast orbit may be a little toocloseto a larger moon called Proteus. Showalter’s team suspects that the new moon likely formed billions of years ago when an icy body from the outer solar system smashed into Proteus — tossing debris into orbit that later coalesced to form the small moon, which they named Hippocamp after a sea creature in Greek mythology.

“We’re basically seeing a chip off of Proteus itself,” Showalter said.

The findings highlight the challenges in making discoveries in the years since the Voyager flyby. “Uranus and Neptune have been neglected in the history of space exploration,” Showalter said. “There’s a big hole in our understanding of the outer solar system.”

When Voyager 2 zipped past Neptune in 1989, it revealed a dynamic world with winds that whip and churn through its atmosphere at speeds as high as 1,500 mph. Its blue atmosphere was also marked by a dark blemish nicknamed the Great Dark Spot. And while it was reminiscent of Jupiter’s Red Spot, which has remained intact for hundreds of years, Neptune’s spot vanished roughly five years later. In the years since, other blemishes have come and gone — each a mystery.

As are Neptune’s rings and moons. From Earth, the rings appear to clump together into partial rings, or arcs, unseen elsewhere in the solar system and previously thought impossible (any such material in orbit around the planet should stretch into a continuous ring). But Neptune’s arcs persist and astronomers cannot say why.

And Neptune’s largest moon, Triton, is an oddity in more ways than one. It hosts geysers that hurtle nitrogen gas 5 miles into the atmosphere, and might be linked to a subsurface ocean. Its surface is constantly being remodeled, which hints at active geology. And Triton might not even be a native to Neptune at all — but a refugee from the Kuiper belt (that distant field of frozen fossils that is home to Pluto and the recently visited Ultima Thule).

Only a closer look could explain these mysteries. Studying Neptune and Uranus could also have implications for our understanding of thousands of worlds detected in orbit around distant stars. Data from the Kepler Space Telescope suggests that ice giants might be the most common type of planet in the galaxy.

“It’s kind of ironic — the Neptune-like exoplanets are far more common than the Jupiter-like exoplanets, yet we’ve studied Jupiter here in our own solar system far more intensively than we have either Uranus or Neptune,” Verbiscer said.

Astronomers, however, think the tide is turning. In a survey produced every 10 years by an expert committee that ranks funding priorities for NASA, a mission to the ice giants was ranked third after missions that would return samples from Mars and visit Jupiter’s moon Europa. Given that scientists have made headway on the first two, a mission to these blue orbs might have good prospects in the near future.

“I’m hoping that it might be time to turn toward this gap in our knowledge and fill it in,” Hammel said.

This article originally appeared in <a href="https://www.nytimes.com/2019/02/20/science/neptune-moon-hippocamp.html" id="28297c79-360e-326e-ac38-efdeca22a7c1">The New York Times</a>.

Neptune Has Another Moon. What Else Is That World Hiding?

It’s time to add one more tiny moon to Neptune’s icy family tree. Astronomers using the Hubble Space Telescope have spied a previously undetected satellite around the solar system’s eighth planet, bringing its total number to 14.

Seth Moran is worried about Mount Hood.

In the 1780s, the volcano rumbled to life with such force that it sent high-speed avalanches of hot rock, gas and ash down its slopes. Those flows quickly melted the snow and ice and mixed with the meltwater to create violent slurries as thick as concrete that traveled huge distances. They destroyed everything in their path.

Today, the volcano, a prominent backdrop against Portland, Oregon, is eerily silent. But it won’t stay that way.

Mount Hood remains an active volcano — meaning that it will erupt again. And when it does, it could unleash mudflows not unlike those from Colombia’s Nevado del Ruiz volcano in 1985. There, a mudflow entombed the town of Armero, killing roughly 21,000 people in the dead of night.

On Mount Hood, “any little thing that happens could have a big consequence,” said Moran, scientist-in-charge at the federal Cascades Volcano Observatory.

And yet the volcano is hardly monitored. If scientists miss early warning signs of an eruption, they might not know the volcano is about to blow until it’s too late.

Determined to avoid such a tragedy, Moran and his colleagues proposed installing new instruments on the flanks of Mount Hood in 2014. Those include three seismometers to measure earthquakes, three GPS instruments to chart ground deformation and one instrument to monitor gas emissions at four different locations on the mountain.

But they quickly hit a major hiccup: The monitoring sites are in wilderness areas, meaning that the use of the land is tightly restricted. It took five years before the Forest Service granted the team approval in August.

The approval is a promising step forward, but Moran and his colleagues still face limitations, including potential legal action that may block their work.

Such obstacles are a problem across the United States where most volcanoes lack adequate monitoring. Although federal legislation passed in March could help improve the monitoring of volcanoes like Mount Hood, scientists remain concerned that red tape could continue to leave them blind to future eruptions, with deadly consequences.

Listening for Rumbles and Belches

The United States is home to 161 active volcanoes, many of which form a line along the west coast through California, Oregon, Washington and Alaska. Seven of the 10 most dangerous American volcanoes are within the Cascade Range, and six of those are not adequately monitored.

In contrast, countries like Japan, Iceland and Chile smother their high-threat volcanoes in scientific instruments.

“The U.S. really doesn’t have anything to this level,” said Erik Klemetti, a volcanologist at Denison University in Ohio.

Yet there is no question that better monitoring could save lives. Volcanoes don’t typically erupt without warning. As Mount St. Helens awoke in May 1980, a series of small earthquakes could be felt on the surface nearby. Shortly thereafter, the volcano started to deform. Steam explosions sculpted a new crater, while a bulge emerged on the volcano’s north flank. Earthquakes continued, landslides rumbled and ash-rich plumes erupted — all before the main event.

Although not all volcanoes follow such a steady, preeruptive pattern, they typically either tremble, deform or belch volcanic gases — meaning that if scientists monitor these three signals, they will likely be able to forecast when a volcanic eruption will happen.

Take Hawaii as an example. Shortly after earthquakes picked up at the Kilauea volcano on April 30, 2018, scientists at the Hawaiian Volcano Observatory could tell that they were not only increasing, but they were also propagating to the east.

“That was not only cool, it was vital for emergency management,” Moran said.

Scientists used those signals to project where magma might erupt, and planners evacuated residents in that area. The eruption destroyed more than 700 homes, but remarkably no one died.

And it was all thanks to 60 seismic stations located across the island.

“Without those instruments, we would have been blind,” said Tina Neal, the scientist-in-charge at the Hawaiian Volcano Observatory. “While we would have known something was happening, we would have been less able to give guidance about where and what was likely to happen.”

Nature’s Bill of Rights

Moran and his colleagues had that example in mind as they pressed their case for adding instruments to Mount Hood.

They submitted a proposal to the Forest Service in 2014. But the instruments — which will be housed in 4-feet-tall boxes with radio antennas and solar panels on the outside — violate the Wilderness Act, which prohibits any new structures and even noise pollution within federal wilderness areas.

“I see the Wilderness Act as nature’s bill of rights,” said George Nickas, executive director of Wilderness Watch, a conservation group that opposed volcano monitoring in federal wilderness. “I think it is so important to have places like that where we can just step back, out of respect and humility, and appreciate nature for what it is.”

In reviewing Moran’s proposal, the Forest Service provided the public with an opportunity to comment, during which they received more than 2,000 statements — most of which agreed that the wilderness needs safeguarding.

To Jonathan Fink, a geologist at Portland State University who also wrote a public comment in favor of volcano monitoring, this argument is misplaced.

“I’m all for protecting wilderness,” Fink said. “But this is just a question of public safety. And I think letting a helicopter in to put some instruments in that can then be monitored remotely seems like a pretty minor exception to the wilderness policies.”

Even so, many critics argue that we cannot make even a single exception — or there won’t be wilderness at all.

“It’s not wilderness if you have structures, if you have roads, if you have motorization,” said Gary Macfarlane, Wilderness Watch’s president. “In fact, it’s antithetical to the whole idea of wilderness.”

Lessons from Mount St. Helens

Other critics say the project is far from necessary. “If we can do something like land one of those landers on Mars, we can move a few miles back from a volcanic feature and monitor it from a little further away,” said Bernie Smith, a retired employee of the Forest Service who wrote a public comment against the project.

But Moran and others argue that the work is not possible unless they get up close, and before the volcano begins to rock.

“The name of the game is to be able to detect and correctly interpret these warning signs as soon as possible — to give society as much time as possible to get ready,” Moran said.

When Mount St. Helens first began to rumble, scientists couldn’t tell if the quakes originated under the volcano itself or 5 miles away at a nearby fault. They only had one seismometer 2 miles to the west of the volcano. So they rushed to place more instruments on its slopes (a risk that would not be allowed today) and within days they knew the volcano itself was shaking.

“Looking back on it, it’s really miraculous that they were able to do what they did,” Moran said.

Scientists have since learned that we don’t always get as much time as Mount St. Helens allowed. At Calbuco, a volcano in southern Chile that’s similar to the volcanoes in the Cascades, all was quiet during the early afternoon of April 22, 2015. But tremors began in the late afternoon, and by 6:04 p.m. local time, the mountain was sending a plume of gas 10 miles into the sky.

With such a narrow window, the first line of defense is to have a solid monitoring network in place whenever a volcano awakens.

“You’re going to either get in there ahead of time and put in the instrumentation you need, or you’re just going to accept that you’re going to go blind into the entire eruptive period and whatever happens, happens,” said Jacob Lowenstern, a geologist with the U.S. Geological Survey.

Not If, But When

Although none of these volcanoes appear to be building toward an eruption today, there is no question that they pose a serious hazard.

“The USGS has a deep understanding that these volcanoes are going to erupt again — within our lifetimes, our children’s lifetimes,” said Carolyn Driedger, a hydrologist at the Cascades observatory. “The evidence is all there.”

Beyond Mount Hood, Mount Rainier near Seattle could also unleash viscous volcanic mudflows. There, 80,000 people live in the path of disaster and yet the mountain only has 19 instruments, which scientists say is not enough given its vast size.

And even volcanoes that don’t loom so close to populated areas could have far-reaching effects.

Glacier Peak in northern Washington has produced some of the most explosive eruptions in the contiguous United States, meaning the ability to throw enough ash into the air to halt air traffic for days or even weeks and cost billions of dollars. It has only one seismometer.

Without equipment to detect the eruption, airplane passengers just might find themselves living a high-altitude nightmare. In 1989, a Boeing 747 flew through an undetected ash cloud in Alaska. All four engines shut down and the airplane went into a nose-dive. It descended 13,000 feet before the pilots were able to restart the engines. Hundreds of thousands of people fly across the West Coast and above active volcanoes every day.

Eruptions in Alaska and California would also be felt across the nation. Anchorage is a major cargo hub, meaning that many FedEx or UPS packages travel through Alaska. But an eruption might bring that to an alarming halt. And because California produces a large portion of the nation’s food, an eruption might limit the fruits and vegetables found at supermarkets as far as the East Coast.

“We’re not just doing this for academic purposes. This is so we can give good information to emergency managers,” Driedger said. “That’s the end in all of this.”

Hoping for Slumber

Despite the permit’s recent approval, Driedger notes that there are still a number of steps before any instruments can be placed on Mount Hood. They will now have to choreograph the assembly of instruments, hire personnel and schedule helicopter trips around weather and other potential obstacles.

Moreover, the Forest Service and the observatory could still face a legal challenge from Wilderness Watch or other groups that adds years to the installation, if not blocking it altogether.

“This is more proof that the Forest Service has abandoned any pretense of administering wilderness as per the letter or spirit of the Wilderness Act,” said Macfarlane, whose group is discussing litigation with an attorney but has not yet decided whether to file suit.

And then there is more work to be done monitoring other hazardous volcanoes beyond Mount Hood.

Volcanologists across the nation were pleased this March when Congress passed the National Volcano Early Warning and Monitoring System Act, which seeks to ensure that volcanoes nationwide are adequately monitored.

But the bill is only an authorization — meaning that Congress has not actually invested the $55 million over five years required to apply for new permits, install more equipment and pay to monitor 34 of the nation’s most dangerous volcanoes. Nor will it change the fact that scientists like Moran must still grapple with regulations protecting federal wilderness.

So Moran, aware that litigation is a possibility, is moving forward with caution. This month, his team will begin to install monitoring stations at Mount Hood. He then hopes the Forest Service will issue a permit to install equipment at Glacier Peak, then turn back to Washington’s Mount Baker. Eventually he would like to install more instruments on Mount Hood, but first he needs to create sufficient networks elsewhere.

While they wait, Moran and his colleagues will hold their breath, hopeful that these volcanoes stay in a deep slumber, but aware that one just might rouse at any moment.

We're Barely Listening to America's Most Dangerous Volcanoes

(Science Times)

<h1>Later this year, NASA will reveal never-before-seen morsels of the moon, the agency announced Monday.</h1>

The astronauts of the Apollo missions that landed on the moon from 1969 to 1972 collected 842 pounds worth of lunar rocks, core samples, pebbles, sand and dust. Many of those samples were later opened on the ground. But three have remained sealed — their contents stashed away for nearly 50 years.

They were intentionally saved for a time when more advanced technology would allow planetary scientists on Earth to delve deeper into the moon’s mysteries.

“The technology available in the ‘60s and ‘70s wasn’t able to do what we can do now,” said Jessica Barnes, an astronomer soon to join the University of Arizona’s Lunar and Planetary Laboratory. “Now we can go to a mineral and we can look at the very fine details, down to almost the width of a human hair.”

In a year marking the 50th anniversary of the Apollo 11 landing, and with U.S. space priorities shifting toward a return to the moon, NASA has at last decided that it’s time to open the long-locked samples. The agency selected nine teams to study the moon rocks in detail.

For the past decade, Charles Shearer, a scientist at the University of New Mexico, has pressed NASA to unseal the rocks. He was thrilled by the news: “We are completing the Apollo mission adventure after 50 years, using new types of measurements and new views of our moon.”

Darby Dyar, a scientist at Mount Holyoke College, agreed. She first studied lunar samples in 1979, as an undergraduate, and has come full circle as a leader of one of the selected teams.

Dyar and her colleagues will scour materials from Apollo 15, 16, and 17, searching for yellow, orange and green glass beads roughly the size of a grain of salt. Those beads formed when the droplets within fire fountains — picture an Old Faithful of lava — hit the lunar atmosphere and cooled.

“Imagine spraying a squirt gun of hot lava,” Dyar said. “Because the droplets are so tiny, they cool immediately.”

And those cooled droplets, or glass beads, are a treasure trove for scientists. They provide a window into the interior of the moon, and could answer fundamental questions about how our nearest neighbor evolved.

The moon’s history is a common theme in many of the selected projects. Kees Welten, a scientist at the University of California, Berkeley, and his team will study a core collected by Harrison Schmitt and Gene Cernan, the Apollo 17 astronauts, in order to better gauge the impact history of the moon. That can be used as a proxy for other planets in the solar system (including Earth) whose craters long-ago disappeared.

Other teams are looking toward the future.

Barnes and her colleagues will analyze four rocks collected from the same site where Apollo 17 landed. Chemically, the samples are very similar to one another — except one was chilled to -20 degrees Celsius within a month of return. It has remained in cold storage ever since.

But scientists are unsure whether freezing the samples is a better storage method than keeping samples at ambient laboratory temperatures. By comparing the chilled sample with the room-temperature samples, the team will be able to assess the frozen curation technique for the first time.

“We’ve never had the opportunity do this kind of study,” Barnes said. “It’s a unique chance to get at a currently unanswered question that’s really important for future sample return missions.”

Those missions include a Japanese spacecraft, Hayabusa2, which currently is collecting samples from the Ryugu asteroid; an American spacecraft, Osiris-Rex, which will collect samples from the Bennu asteroid; and future missions to the moon and Mars.

Clive Neal, a scientist at the University of Notre Dame who will work with Shearer on another team, said that preparing for future missions to the moon makes it important to open the lunar samples now.

“We did have the technology 10 years ago, but we didn’t have the drive,” Neal said. “Now, we’re going back to the moon and we need to use lunar resources in order to do it sustainably.”

That was made possible in 2008, when scientists discovered that the moon was not bone dry, but contained water. With water, future astronauts might be able to quench their thirst, and they also will be able to split its molecules into oxygen, to breathe, and liquid hydrogen, to refill their fuel tanks — thus helping sustain a lunar outpost.

But scientists can’t yet pinpoint how much water is on the moon, Neal said: “That starts with this particular project of these unopened Apollo samples.”

This article originally appeared in <a id="f38eab94-b598-49d7-a517-72041b5f34c2" href="https://www.nytimes.com/2019/03/13/science/moon-rocks-nasa.html">The New York Times</a>.

Sealed Cache of Moon Rocks to Be Opened by NASA

They were intentionally saved for a time when more advanced technology would allow planetary scientists on Earth to delve deeper into the moon’s mysteries.

Sealed cache of moon rocks to be opened by NASA

<h1>It’s time to add one more tiny moon to Neptune’s icy family tree. Astronomers using the Hubble Space Telescope have spied a previously undetected satellite around the solar system’s eighth planet, bringing its total number to 14.</h1>

The discovery, formally reported Wednesday in Nature,is a reminder that there is much more to be found in our own backyard, with implications for our understanding of worlds around other stars in our galaxy.

That’s especially true for Uranus and Neptune, which are known as the ice giants. While every other planet in our solar system has been poked and prodded by multiple spacecraft, these two remain largely unexplored. Voyager 2 did swing past Neptune 30 years ago, but the spacecraft was moving too fast and was limited by technology designed in the 1970s.

Mark Showalter, a researcher at the SETI Institute in Mountain View, California, was analyzing Neptune’s rings with a new technique to process old images. To his surprise, a tiny white dot appeared. Further analyses have confirmed that it is a moon, and a rather odd one.

Showalter’s team suspects that the new moon, which is roughly 20 miles in diameter, likely formed billions of years ago when an icy body from the outer solar system smashed into a larger moon, Proteus — tossing debris into orbit that later coalesced to form the small moon, which they named Hippocamp after a sea creature in Greek mythology.

The findings highlight the challenges in making discoveries in the years since the Voyager flyby.

“Uranus and Neptune have been neglected in the history of space exploration,” Showalter said. “There’s a big hole in our understanding of the outer solar system.”

This article originally appeared in <a id="781465f5-df9c-459b-80a4-05a236a8d383" href="https://www.nytimes.com/2019/02/20/science/neptune-moon-hippocamp.html">The New York Times</a>.

Closer look at Neptune reveals another moon, and a blind spot for astronomers

The discovery, formally reported Wednesday in Nature,is a reminder that there is much more to be found in our own backyard, with implications for our understanding of worlds around other stars in our galaxy.

<h1>The north magnetic pole is restless.</h1>

Distinct from the geographic North Pole, where all the lines of longitude meet at the top of the world, the magnetic pole is the point that a compass recognizes as north. At the moment, it’s 4 degrees south of the geographic North Pole, which lies in the Arctic Ocean at 90 degrees north.

But that wasn’t always the case.

In the mid-19th century, the north magnetic pole floated much farther south, roaming around Canada. For the past 150 years, however, the pole has been sprinting away from Canada and toward Siberia.

That change of address cannot be ignored, given that magnetic compasses still underpin modern navigation, from the systems used by civilian and military airplanes to those that orient your iPhone.

In 1965, scientists began a data-based representation of Earth’s magnetic field in order to better keep track of the pole’s ever-changing home. The World Magnetic Model is updated every five years — most recently in 2015 — because the magnetic field is constantly shifting.

In early 2018, it became clear that 2015’s edition was in trouble, because the pole’s Siberian stroll had picked up speed, rendering the model — and therefore a number of navigational systems — incorrect.

So for the first time, scientists have updated the model ahead of schedule, which they released Monday afternoon. Since this work was completed in the wake of the partial government shutdown (which delayed its full release), researchers are still trying to get a handle on the mysteries within Earth’s core that must be driving the magnetic pole’s surprising behavior.

A Continuous Makeover

The north magnetic pole’s dizzying dance was discovered nearly 400 years ago, when Henry Gellibrand, an English mathematician, realized that it had jumped hundreds of miles closer to the geographic pole over the course of 50 years.

“That was a big, monumental recognition that the field was not static, but dynamic,” said Andrew Jackson, a geophysicist at ETH Zurich.

It didn’t take long, however, before magnetic north flipped direction and started to move away from the geographic pole — demonstrating that the field is not just dynamic, it’s unpredictable.

“The problem that we’re still facing today is that we don’t have a good scheme to predict how the field will change,” Jackson said.

So scientists began tracking the ever-changing magnetic field. The first magnetic maps, which were hand-drawn by exploring sailors, revealed that for the next two centuries, magnetic north twirled among the many islands and channels of the Arctic Archipelago.

Then around 1860, it took a sharp turn toward Siberia. Since then, the pole has traveled nearly 1,500 miles and was most recently found in the middle of the Arctic Ocean, still en route to Russia.

Scientists attribute this wanderlust to the liquid iron sloshing within our planet’s outer core. That iron is buoyant — it rises, cools and then sinks. And that motion below carries Earth’s magnetic field with it, producing changes above.

To more accurately map those changes, scientists launched the precursor to the World Magnetic Model nearly 55 years ago, which began as a collaboration between the United States and Britain.

The map we know today has existed in its current form since 1990 and is created by an agency within the National Oceanic and Atmospheric Administration and the British Geological Survey. It’s commissioned by U.S. and British military agencies, and used by many other militaries across the world.

Alongside GPS, navigational systems used by satellites, aircraft, ships and other vehicles rely on magnetic compasses to ensure they’re moving in the correct direction. Perhaps the most visible sign of this can be found at the end of every airport runway, where large white numbers reflect the runway’s magnetic heading.

But as the magnetic field shifts, those headings change and runways get a makeover. This year, for example, the runways that make up the Dwight D. Eisenhower National Airport in Wichita, Kansas, will receive new names that match their new headings. The process — which includes repainting the huge numbers at the end of each runway and replacing other signage — is likely to cost several hundred thousand dollars.

And it all depends on the World Magnetic Model, which is not easy to build. Unlike the kilogram or the second, the magnetic field cannot be defined once and then used for decades.

“The magnetic field is constantly changing,” said Susan McLean, the retired chief of the geophysical sciences division at NOAA, who helped set the magnetic model in the past. “It changes with time. It changes with location. And it changes the way it changes.” Tracking the planetary magnetic field, she added, is more akin to forecasting the weather.

And like the weather, perfectly predicting where the pole will move is downright impossible. But scientists can get close with a wealth of data collected from satellite and ground-based observatories. That data allows them to deduce how the magnetic field has changed over the past several years and to extrapolate into the future with a model that will — hopefully — remain accurate for the next five years.

The Pole’s Pilgrimage

After scientists released the World Magnetic Model in 2015, they periodically checked it against field measurements to ensure that it was accurately predicting variations in Earth’s magnetic field. When they ran that check in early 2018, they discovered that the model and reality were out of alignment.

“We noticed that the error in the Arctic was increasing faster than what we would expect,” said Arnaud Chulliat, a geophysicist at the University of Colorado at Boulder and NOAA.

Although the north magnetic pole has long been scurrying away from Canada and toward Siberia, the rate of its movement drastically changes. Throughout most of the 20th century, it drifted at roughly 6 miles per year. In the 1980s, it picked up speed, and by the year 2000 it was traveling at 35 miles per year on the way out of Canada.

Then, in 2015, the pole slowed to 30 miles per year. So when the team issued the most recent magnetic map, scientists predicted that the speed would continue dropping — only it didn’t.

Just after the model was released, the north magnetic pole picked up momentum again, and now it is fluctuating at around 35 miles per year. In late 2017, the pole crossed the international date line into the Eastern Hemisphere.

“It’s not the fact that the pole is moving that is a problem, it’s the fact that it’s accelerating at this rate,” said William Brown, a geophysicist at the British Geological Survey. “The more acceleration or deceleration there is, the harder to predict where the thing is going to be.”

And that means the model is currently incorrect — at least, in the Arctic.

While many of us might not spend much time — or any time — at the top of the world, some international airline flights fly close to the geographic North Pole. They need the magnetic model to be accurate for safe journeys.

If you were to use the current model to travel to the north magnetic pole, you would end up 25 miles away from where the pole actually resides.

So scientists raced to fix the model by feeding it several years of recent data. Together, BGS and NOAA have made a new version available.

But efforts to finish the revision on publicly available online systems maintained by NOAA were delayed by the partial government shutdown in the United States. The researchers were able to complete the update Monday.

The public maps will have many uses, from recalculating runway names to ensuring that Defense Department systems are properly installed. Engineers incorporate the model into the navigation systems on your smartphone and in your car.

But for most people at low- and mid-latitudes, the current model is safe to use.

“South of 65 degrees north and away from Canada, the average user will notice very little difference to their daily life,” said Ciaran Beggan, a geophysicist at BGS.

Geomagnetic Apocalypse? Probably Not

With the updates complete, scientists are eager to understand the causes of the pole’s Siberian sprint. “It’s clear that something strange is happening,” said Phil Livermore, a geophysicist at the University of Leeds in England.

On multiple occasions during Earth’s long history, the magnetic field has weakened significantly. The north magnetic pole slipped toward the bottom of the planet, and the south magnetic sauntered toward the top. The process took a few thousand years, but by the time the field’s full strength returns, it has flipped.

The pole’s recent journey, along with other changes — like a weakening of Earth’s magnetic field — has led some scientists to wonder whether such a reversal might be around the corner, geologically speaking.

“It does tick off some of the boxes of magnetic reversal,” said Courtney Sprain, a geophysicist at the University of Liverpool in England, who added that “we definitely can’t say that for sure.”

Most scientists, including Sprain, doubt an impending geomagnetic reversal. First, while the north magnetic pole does appear to be on the move, it doesn’t represent a global phenomenon, just a regional one.

Livermore thinks there are two large magnetic structures in the planet’s outer core, one beneath Canada and one beneath Siberia, which interact together to emit the magnetic pole.

The Canadian patch is weakening, which means that it’s essentially losing a tug-of-war, causing the north magnetic pole to turn toward Siberia, while the south magnetic pole is standing relatively still.

Second, while Earth’s magnetic field is weakening, many experts say it’s still above the long-term geologic average.

Peter Olson, a geophysicist at Johns Hopkins University, thinks that the current changes represent a transient fluctuation and not a reversal.

Even if the magnetic field were on the edge of a flip, scientists argue that it’s not an apocalyptic scenario. Although the field provides essential protection from the sun’s powerful radiation, fossil records reveal no mass extinctions during past reversals.

And whatever the risks to power grids and communications, humanity would have ample time to prepare.

“Of all the problems we have, this is not a top 10 problem,” Olson said.

This article originally appeared in <a id="cd0c77a8-2e82-4a28-940b-759b1d0f8042" href="https://www.nytimes.com/2019/02/04/science/north-magnetic-pole-model.html">The New York Times</a>.

In the mid-19th century, the north magnetic pole floated much farther south, roaming around Canada. For the past 150 years, however, the pole has been sprinting away from Canada and toward Siberia.

This North Pole is on the move

<h1>In the wee hours of Thursday (12:19 a.m. Eastern time, to be exact), Earth will make its closest approach to the sun and reach a point in its orbit known as perihelion. Chilly as winter may feel in the Northern Hemisphere, we are more than 3 million miles closer to our fiery star than we were in the dead of summer.</h1>

The change in distance occurs because our planet’s orbit is stretched into an ellipse — so Earth snuggles up to the Sun every January and dips farther out into the outer solar system every July, at a point known as aphelion.

Although 3 million miles sounds vast, it’s not much on the scale of our solar system. In fact, despite the planet’s elliptical path through the heavens, most astronomers say that Earth’s orbit is basically circular. On a scale of 0 to 100 percent, where 0 is a perfect circle and nearly 100 is a very thin oval, Earth only scores a 1.7.

It is a defining trait that keeps our planet at roughly the same distance from our sun, and keeps the climate relatively stable. This has led many astronomers to wonder whether a circular orbit just might be a crucial ingredient in the cocktail of life — and a key factor to consider as they search for signs of alien life around the thousands of exoplanets known to be circling other stars within the galaxy.

Consider the exoplanet known as HD 20782 b, which boasts the highest orbital eccentricity yet discovered — a whopping 97 percent. Although the alien world is likely more akin to Jupiter than Earth in mass, it is easy to imagine what might happen to a wildly eccentric Earthlike planet.