Category Archives: lectures

Six things you may not know about NASA

NASA turned 60 on October 1, 2018 and last weekend the Museum of Flight hosted a talk by the agency’s chief historian, Bill Barry, as part of the anniversary celebration. Since we all know about the Moon landing, the space shuttle program, explorations of the planets, the Hubble Space Telescope, the International Space Station, and various NASA research and discoveries, Barry focused his talk on six things you may not know about NASA.

#6: NASA science data saved us from disaster

In a day and age when there’s significant distrust of science, it’s interesting to note NASA’s role in solving a difficult environmental problem. Researchers as early as the late 1950s noticed that there was a depletion of ozone in the atmosphere above the South Pole, but it was difficult to document.

Bill Barry

NASA chief historian Bill Barry gave a talk at the Museum of Flight Oct. 6, 2018 celebrating the 60th anniversary of the creation of the agency. Photo: Greg Scheiderer

Barry explained that NASA used the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus 7 weather satellite to confirm and map the hole in the ozone.

“It was pretty clear that the ozone hole was big and getting bigger,” Barry said, and that got people’s attention. Scientists postulated that the ozone depletion was caused by chemical reactions with chlorofluorocarbons (CFCs) such as refrigerants and spray-can propellants, but again it was tough to prove. Observations made from NASA’s ER-2 aircraft and DC-8 Flying Laboratory eventually confirmed that the CFCs were the culprit.

This led to an amazing act of international cooperation on an environmental issue. In the Montreal Protocol in 1987 nations agreed to phase out CFCs and other ozone depleting substances. It’s working; Barry noted that the ozone is gradually recovering.

“Demographers suggest that this action saved us at least two million cases of skin cancer,” since then, he said.

#5: NASA almost didn’t happen

At the dawn of the space age, after Sputnik, the military became keenly interested in spy satellites and possible space weaponry. US Secretary of Defense Neil McElroy created the Advanced Research Projects Agency (ARPA), which later became the Defense Advanced Research Projects Agency, with the aim of collaborating with academic, industry, and government partners on military programs involving space.

Dryden

Hugh Dryden was director of NACA from 1947 until NASA was formed in 1958. Photo: NASA

In the meantime over at the National Advisory Committee for Aeronautics (NACA) director Hugh Latimer Dryden had pushed the committee’s research agenda toward high-speed flight and space research. In January 1958 he wrote a key report suggesting that space efforts be a collaboration between the DOD, NACA, National Academy of Science, research institutions, universities, and industry. That’s pretty close to the ARPA mission, with a civilian bent.

Barry said that within about a month of the issuance of Dryden’s report, President Dwight Eisenhower went along with it, and sent Congress proposed legislation creating the National Aeronautics and Space Agency. Congress soon approved it.

In the early days of the collaboration there was still arm wrestling over control. A memo from Eisenhower directed that NASA would run all programs “except those peculiar to or primarily associated with military weapons systems or military operations.” The DOD took a broad definition of that—figuring putting people in space was military and so that was within their bailiwick. Eisenhower intervened to clarify that the legislation made NASA a largely civilian organization.

“This key decision on Eisenhower’s part was really important,” Barry said. “NASA in some ways has become the world’s space agency, one of the most positive aspects of US international relations,” and the civilian nature of the agency is vital to that.

#4: NASA is a serial creator of new industries

Barry pics

Barry said smartphone cameras with CMOS chips may be as good or better than DSLR cameras, so we put it to the test. Smartphone pic is on the left. Problems may be due to operator error! Photos: Greg Scheiderer

There’s a common belief that Tang, Teflon, and Velcro were creations of the space program. Barry said those aren’t correct, but a lot of other stuff has NASA origins. Excimer lasers developed for ozone detection proved useful for laser surgery, for example, and the complementary metal-oxide semiconductor (CMOS) chips in your smartphone camera were originally developed to build a better camera for space probes. Oddly, those never flew, but they’ve taken off here on Earth. NASA’s annual Spinoff magazine highlights stuff that originated in the space program.

Beyond those, NASA has spun off entire industries. Weather satellites and communication satellites (now a $2 billion/year industry) came from NASA. Under COTS (Commercial Orbital Transportation Services) companies such as SpaceX and Boeing are building crewed vehicles and plan to begin testing next year.

“We hope by the end of next year to be launching US astronauts from Florida again up to the International Space Station and paying American companies to do it for us,” Barry said.

#3: NASA revolutionized the understanding of the universe

One’s first response to that is, “Well, duh!” but Barry said it’s easy to take for granted what has happened over the last 60 years.

“We don’t often think about how much things have changed since 1958 when NASA was created,” he said. Sixty years ago otherwise sane people thought there may be civilizations and canals on Mars and dinosaurs on Venus. They figured the outer solar system was just boring ice. There were nine planets; we now know that virtually every star has at least one. We had no idea the Van Allen Belts existed. Now we have a photo of the cosmic microwave background.

#2: Why did we go to the Moon?

President John F. Kennedy wasn’t actually that big on space; in early speeches after he was sworn in he kept proposing that the US and Soviet Union team up on space projects.

The Soviet Union wasn’t too keen on that. They were using the success of their space program to proclaim the superiority of their system and to recruit allies in a world that had been “decolonized” after World War II. The Soviets were winning the propaganda war. JFK wanted a way to beat them without breaking the bank.

Trailing in the game, Kennedy moved the goalposts and declared the race to the Moon.

“The Soviet Union’s success in space was a major strategic strategic problem for the United States,” Barry explained, “so investing money in going to the Moon was a way to prove that the western, capitalist model of government was, in fact, at least as good as if not better than the Soviets.”

#1: The race to the Moon was closer than you think

JFKJFK made his speech to Congress about setting the goal of “landing a man on the Moon and returning him safely to the Earth” in May of 1961, shortly after Yuri Gagarin became the first man in space. It wasn’t until years later, with President Lyndon Johnson pushing the goal as Kennedy’s legacy, that the Soviets took notice.

“It’s really obvious by the summer of 1964 that the US was serious about going to the Moon and had the political will and the money to make it happen,” Barry said.

The Soviet response was the Zond program. They wouldn’t orbit the Moon, but would instead fling their spacecraft around it and then return to Earth.

The Soviets made five Zond launches in 1968 had a few successes. Zond 5 in September took some tortoises and other life forms along and landed back on Earth, though in the Indian Ocean rather than on land as intended. Zond 6 made the trip and landed on target in Kazakstan, but its heat shield failed. Tests weren’t going well on the N-1 rocket, the Soviet counterpart to the Saturn V that would be their way of launching people to the Moon. In December 1968 Apollo 8 and three US astronauts orbited the Moon.

“It was pretty clear they weren’t going to get their guys on the surface of the Moon before we did,” Barry said. But the Soviets didn’t give up. They sent up a Hail Mary.

The Soviets had been launching Luna spacecraft since the late 1950s, and in the space of six months they cobbled together a robotic craft that would land on the Moon, collect a few rocks, and bring them to back Earth.

A first launch attempt failed, but Luna 15 blasted off three days before Apollo 11. The Eagle got to the Moon first. Neil Armstrong and Buzz Aldrin did their Moon walk and were catching a few winks before launching to return to the command module Columbia.

“While they’re sleeping in the lunar module the Soviets fired the retro rockets on Luna 15 and landed on the surface of the Moon. It crashed,” Barry said. But he added that if it had landed successfully, the Soviets may well have been able to get their Moon sample back to Earth first.

“The race to the Moon ends July 20, 1969 after the first Moon walk actually happened,” he marveled. “It was that close.”

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Waffles and big data in the universe

Waffles and big data were on the menu at the most recent gathering of Astronomy on Tap Seattle at Peddler Brewing Company in Ballard.

Leah Fulmer

Fulmer at work. Photo: Astronomy on Tap Seattle

Leah Fulmer, who is working at the University of Washington on her Ph.D. in astronomical data science, gave a talk titled, “Data-Driven Astronomy in the 2020s and Beyond.” Fulmer explained that we’re in the midst of a “data tsunami” that’s been growing over the last three decades of astronomical surveys.

Back in the 1990s the Palomar Digital Sky Survey and the Two Micron All-Sky Survey each collected about a terabyte of data. That’s a trillion bytes; 1012 bytes. Enough to fill a thousand one-gigabyte smartphones.

The 2000s brought the Sloan Digital Sky Survey (SDSS) and the Galaxy Evolution Explorer. These collected in the tens of terabytes of data. In the 2010s Pan-STARRS collected a petabyte of data; a quadrillion bytes.

In the future this astronomical growth in data collection will continue. The Large Synoptic Survey Telescope (LSST) under construction in Chile will survey the entire night sky every few nights for ten years. It will ultimately collect an astounding 500 petabytes of data—that’s 20 terabytes every single night.

“SDSS had a total data collection of 40 terabytes,” Fulmer pointed out. “We’re going to have one SDSS every two nights in the 2020s. This is a big freaking deal.”

On top of the data, Fulmer noted that the LSST will alert its network when it finds something interesting. Given the amount of data, Fulmer said there will be ten million alerts every night, or about 232 every second.

“This is overwhelming; this is a data tsunami,” she said. “With this sort of data collection astronomers cannot do our science in the way we have up until this point.”

A new way to look at data

Up until recently astronomers would apply for telescope time, make their observations, take the data home, and analyze it. That won’t work in the era of big data for a couple of reasons. First, you can’t jam that much data onto your laptop. Second, there just aren’t enough astronomers to sort through data on objects one by one. As you might guess, we need the help of computers.

“Specifically, we need the help of machine learning,” Fulmer said. This can be both “supervised” and “unsupervised” learning. Astronomers can identify objects by their light curves, and the computers can be taught what those are. That’s supervised. In unsupervised learning, the computers can go out on their own and sort various observations into categories with similar characteristics, and we can figure out what’s in each category.

Once you figure that out, a data broker like ANTARES (the Arizona-NOAO Temporal Analysis and Response to Events System, and yes, astronomers still rule at acronyms) can let the right people know about discoveries in a timely manner.

Fulmer said it’s interesting that ANTARES will never look at the sky, just at data, and that many future astronomers may never visit a telescope, just analyze the data. Different fields can learn from each other about how to process all of this information.

Fulmer finds the era of big data exciting.

“It’s not just data-driven astronomy, it’s data-driven everything,” she said.

Astronomy with your breakfast

N. Nicole Sanchez is working on her Ph.D. in astronomy at the UW, and her research interest is in spiral galaxies like our own Milky Way and how they evolve. This, naturally, led her to think of galaxies as waffles. Thus the title of her talk, “Black Holes, Gas, and Waffles.”

Spiral galaxies form into disks, she explained, and a waffle is a disk. The galaxies have a central bulge, represented on the waffle by a big pat of butter. Marshmallows, suspended by toothpicks, represent globular clusters of stars. Red and blue sprinkles represent old red stars and young blue ones. You just have to imagine the supermassive black hole at the center of the waffle. It may be massive, but it’s super small compared to the size of the waffle.

Sanchez came up with the idea for this model while teaching at the UW in the “Protostars” summer science camp for middle school girls the last couple of years. In the waffle model, syrup represents the gas in the galaxy.

“That’s what you’re making your stars out of, so there’s going to be a lot in your disk,” Sanchez said.

In fact, her faculty advisors got wind of the waffle model and said it would need A LOT of syrup, which led to the hilarious twitter thread below. Click on it to see the academic discussion.

Sanchez admitted that her waffle galaxy may be “a bit too simplified” as a model. But the syrup is important.

“There’s actually tons of gas around really all galaxies, in what’s called the circumgalactic medium,” Sanchez said. The gas is important to the evolution of a galaxy. It feeds the black hole and helps  form stars.

Sanchez studies galaxies by using cosmological hydrodynamic simulations.

“I put a bunch of particles in a box, turn on gravity, and let time happen,” she laughed. After running a simulation she looks for a galaxy similar to the Milky Way, and examines interactions between the galaxy’s supermassive black hole and the circumgalactic medium.

“The supermassive black hole is actually really vital to the evolution of the CGM because it’s moving all of this metal that’s being created in the hearts of stars in the disk of the galaxy and it’s propagating them out into the CGM,” Sanchez explained. Without a supermassive black hole, the circumgalactic medium would not look like what astronomers have observed.

Pass the syrup.

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Exploring the solar system with Emily Lakdawalla

Emily Lakdawalla gushes with enthusiasm about the cool things to see and learn in our solar system, and for her that would be reason enough to explore those places.

“I’m just curious,” she told the Rose City Astronomers at their most recent meeting in Portland. “I like to see the new places, I like to see the planets. I think it’s awfully fun, but that’s not a good reason to make somebody else pay for it.”

Lakdawalla

Emily Lakdawalla (Isabel Lawrence/Planetary Society)

Lakdawalla, senior editor and planetary evangelist for the Planetary Society, said the public policy reasons for exploration are to answer the questions of how we got here and whether we’re alone in the universe. We need to find those answers off-planet.

“Earth is a wonderful planet to live on!” she said. “It’s my favorite planet; it’s temperate, it’s a very comfortable place to live. It’s also a terrible place to try to answer these questions from a planetary science point of view.”

That, she says, is because Earth is dynamic. Forces like weather and volcanism and even life and evolution change things and mess up the ancient evidence about how things were before. We need to go to space to find territory in a more undisturbed state.

After the first wave of planetary exploration, with Viking, Mariner, and the like, enthusiasm and political will and funding for planetary exploration waned. Lakdawalla explained that the Planetary Society was founded in 1980 to be an advocate for finding the answers. We’re now enjoying a second wave of exploration.

“Since the end of the second millennium, we’ve had this amazing expansion of robotic space explorers all over the solar system,” Lakdawalla said. She talked about many of them, with a particular emphasis on Mars. This is squarely within her bailiwick, as she is the author of the book The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job (Springer Praxis Books, 2018).

She explained how a series of Mars missions followed the water. Mars Global Surveyor made a map. Mars Odyssey detected evidence of hydrogen by analyzing neutron movement, and hydrogen could mean water. Phoenix went to look for water and found ice. Mars Express found places where there’s clay, evidence of water, in many places. Curiosity went to one of those places.

“Curiosity has found environments on Mars that are unequivocally habitable,” Lakdawalla said. “Curiosity is not capable of looking for fossil evidence of microbial life on Mars. It doesn’t have the instruments.”

While Curiosity continues its mission, Lakdawalla said we’ve pretty well exhausted this particular line of research.

“We have found that, yes, Mars could have originated life in the past, but we can’t tell you if there was life there or not,” she said. That question will be up to the next line of rovers, such as the ESA’s ExoMars and NASA’s Mars 2020.

Lakdawalla spent some time on the outer solar system, particularly the life possibilities on the jovian moons Ganymede and Europa and Saturnian moons Titan and Enceladus. She noted that on Titan the temperature is such that methane could exist on the surface in liquid, gas, or solid forms, much as water can exist on Earth. The Huygens probe found round rocks on Titan, a significant discovery for a geologist.

“We have a river, except it’s a bizarro river,” Lakdawalla said. “Those rocks are made of water ice, and the river they were tumbled in was a methane river. It’s so familiar and so completely bizarre.” She said it’s hard to say if life could exist in that strange environment. Another reason for further exploration!

Lakdawalla said she’d love to see a mission soon to either Uranus or Neptune.

“They don’t get enough respect,” she said. “I think they’re awesome worlds.” But remembering her statement that coolness alone isn’t enough of a reason for the trip, she noted that the ice worlds are at an intermediate size between the gas giants and the terrestrial planets.

“Most of the exoplanets that we have discovered in the last 30 years have been of this size,” Lakdawalla noted. “We’ve never studied up-close the ones in our own solar system except for one Voyager 2 fly-by. We don’t understand these worlds very well at all, so how are we going to understand the rest of the universe and all of these other planets orbiting all of these other stars?”

Lakdawalla concluded that it’s a great time to be in the planetary exploration business.

“We’re doing it for a reason; we’re trying to understand how we got here, whether we’re the only life in the solar system,” she said. “It’s just a wonderful field of study.”

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The amazing story of New Horizons

The New Horizons spacecraft is hurtling through deep space toward its New Year’s Day encounter with the Kuiper Belt object “Ultima Thule,” a nickname which is better than the object’s official moniker of 2014 MU69. New Horizons collected amazing photos and data during a 2015 fly-by of Pluto, and I’ve just finished reading the account of that mission, Chasing New Horizons: Inside the Epic First Mission to Pluto (Picador, 2018). Penned by New Horizons principal investigator Alan Stern and astrobiologist and author David Grinspoon, Chasing New Horizons is a fabulous read that tells the tale of the nearly 25 years it took to get the mission from a back-of-the-napkin concept to a real spacecraft that delivered those amazing images of the former ninth planet.

Stern and Grinspoon visited Seattle in May in support of the book. Grinspoon called the tale of New Horizons an unlikely story.

“The effort to send a mission to Pluto,” he said, “was one that had so many twists and turns, seeming dead ends, and inescapable traps that it’s still amazing to me that it happened.”

“I think there’s a lot of genuine suspense and drama, and yet, you know how it ends!” Grinspoon added. “It really is an adventure story as well as a nerd-fest of solving technical problems and ultimately succeeding spectacularly in this amazing exploration.”

The story truly is incredible. The New Horizons team that at its biggest included 2,500 people had to battle from the beginning. The first fight was simply getting approval just to do some preliminary work on a project as audacious as sending a mission to Pluto. They had to compete over whose proposed project would be selected, to get funding, to decide what science would happen, to actually build, launch, and fly the craft, to get it to the right place at the right time, and to deliver the science that was promised. Stern said they euphemistically referred to their challenges with the resident reptiles around the Kennedy Space Center in mind.

“There were so many alligators in the water at one point that we had no idea how we could solve all of the problems that we were having,” Stern said.

Yet—spoiler alert!—they did, and they accomplished it for a fraction of the cost of the Voyager mission, for example, and in a time frame that, by NASA standards, was break-neck.

Grinspoon and Stern

Grinspoon (left) and Stern spoke about Chasing New Horizons at a Town Hall Seattle event at the Museum of Flight on May 17, 2018. Photo: Greg Scheiderer

Grinspoon interviewed Stern and more than two dozen others for the book, so it is really something of an oral history of New Horizons team members’ recollections of what happened along the amazing journey.

All of the jockeying makes for interesting storytelling, but the near loss of the mission just days before it’s Pluto fly-by, and how that was solved, is an incredible tale. Many of the team were taking a quick breather before the fly-by and trying to enjoy the Independence Day holiday when contact with New Horizons was lost. The work the team did to figure out what happened, to fix the problem, and to make sure the craft’s computers were ready for the complicated maneuvers ahead, is simply remarkable. Imagine doing that work around-the-clock with the whole mission hanging in the balance. For Stern, there was the real possibility that 25 years of work could go down the drain. That’s a whole lot of egg aimed right at your face. Cool heads, smart engineers, preparation, and a little luck prevailed. The science we got out of it is amazing.

“Pluto is an exotic, sci-fi world,” Stern said. “This book is a page-turner; it is a techno-thriller.”

You don’t necessarily want the author writing his own dust-jacket blurbs, but in this case we agree! Chasing New Horizons is highly recommended.

Last month New Horizons, about 100 million miles away from Ultima Thule, was able to spot its next destination with its own cameras, something the team announced on Twitter.

If you read Chasing New Horizons you’ll have an idea of what the team has ahead between now and its fly-by on January 1.

Further reading:

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Mars is here!

It’s been a big year for Mars. The InSight lander is on the way to the Red Planet, scheduled to land November 26 on a mission to take the vital signs of Mars. There’s a big dust storm on Mars just as it reaches opposition this week, its closest approach to Earth since 2003. Oh, and organics have been found on Mars.

We may have buried the lede on that one.

Mars

July 18 image of Mars by the Hubble Space Telescope. (Image credit NASA, ESA, and STScI)

Dave Cuomo and Keith Krumm from the Pacific Science Center were guest speakers at the July meeting of the Seattle Astronomical Society, and discussed all things Mars.

The discovery of organics on Mars is also evidence that science is not necessarily fast. The work came out of a hole the Curiosity rover drilled in a Mars rock way back in 2015. The papers outlining the discovery just came out earlier this year.

“What it found in a rock that is about three-and-a-half billion years old was organic molecules,” Cuomo said. The substance found was kerogen, which Cuomo called, “a gooey precursor to petroleum.”

Cuomo repeatedly stressed that this does not, not, not mean that there is or ever was life on Mars.

“What we have found is evidence that the building blocks for life on Mars certainly did exist three-and-a-half billion years ago,” he said. “This was the first time that we found clear evidence that this was there.”

Cuomo noted that we know a good bit about the history of the surface of Mars.

“Mars certainly was a warmer and a wetter environment that could have supported life, that life could have evolved on,” he said. “What we don’t know—and this is what InSight is going to help us find out—is how long Mars was more Earth-like.” The longer that warm, wet environment lasted, the greater the potential that life could have arisen.

InSight

Krumm noted that InSight is something of an interplanetary RN.

“It’s going to be taking Mars’ vital signs,” he said. It will use a seismometer to take Mars’s pulse, a heat flow probe to measure its temperature, and the Rotation and Interior Structure Experiment, RISE, will check its reflexes, precisely tracking the location of the lander to determine just how much Mars’ north pole wobbles as it orbits the Sun. Cuomo said a big part of the mission’s purpose is to find out if Mars has a molten core today.

“It has volcanoes, so we know at some point in the past it had a molten interior,” he said. “It had a magnetosphere—the remnants of it are frozen in the rocks—but it does not have an active magnetosphere.”

InSight will help us figure out of the core solidified, or if there’s some other reason for the loss of the magnetosphere. Krumm and Cuomo showed this video about the InSight mission.

The Pacific Science Center plans an event for watching the InSight landing on November 26. Watch this space for details!

Dust storm

The rover Opportunity is powered by solar panels, and the dust storm on Mars has blocked the Sun to an extent that Opportunity has shut down. NASA hasn’t heard from Opportunity since June 10. It’s programmed to switch back on every so often, and shut right back down if it doesn’t find power. Cuomo said that can only go on for so long.

“It’s possible it won’t wake up,” he said. If that happened, it would be a sad end to a tremendous run. Opportunity and its twin, Spirit, landed on Mars in 2004 on missions expected to last 90 days. The last contact with Spirit, stuck in the sand, was in March 2010, while Opportunity, up until last month, at least, has been running for more than 14 years.

Opposition

Mars reached opposition to Earth on the evening of July 26 in Pacific Daylight Time, and will be at its closest approach to Earth for the year on Tuesday, July 31. Those dates are different because of the geometry of the elliptical orbits of the two planets. In any case, we’re closer to Mars than at any time since the great apparition of 2003, which is good news for amateur astronomers. The bad news is that the dust storm could foil our attempts to image and observe surface features of Mars. There was word this week, however, that the storm is fading. Bright red Mars will be a good observing target for the rest of the summer and into early fall.

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LSST to the rescue

We hope the Large Synoptic Survey Telescope (LSST), under construction in Chile on a timeline that would have it begin science work in 2022, works. There are a bunch of astronomers banking on it to make their lives a lot easier. A group of them—the LSST Solar System Science Collaboration—met earlier this month in Seattle, and four of them gave talks at a special edition of Astronomy on Tap Seattle at Peddler Brewing Company in Ballard.

David Trilling of Northern Arizona University noted that the LSST will have an 8.4-meter mirror and a camera the size of a small car.

“In terms of telescopes, this is a really, really, really big machine,” he understated. That car-sized camera will boast 3.2 billion pixels.

“You’d need 1,500 HDTV screens to look at a single LSST image,” Trilling said. LSST will scan the entire night sky every three to four nights for ten years.

“That’s about ten terabytes of data every night, which is a huge computational challenge,” he noted.

It’s an asteroid. It’s a comet. It’s complicated…

Michael Mommert of Lowell Observatory studies asteroids and comets. He said that sometimes it’s difficult to tell one from another. An asteroid can look like a comet if the asteroid is “active.” This could be because it collided with something else, or it is spinning rapidly, or it was warmed by its proximity to the Sun.

“If we can understand those active asteroids we can better understand the average asteroid,” Mommert said. “We can learn a lot about the mechanisms that are going on in asteroids from those active asteroids.”

Similarly comets can go dormant, with no tail, and look more like asteroids. As they often share similar properties, Mommert said comets and asteroids are on something of a continuum rather than being two distinct types of objects.

In his research Mommert is tracking about 20 active asteroids and 50 dormant comets. He figures he spends 30 nights per year using a telescope. He’ll be able to cut down that time tremendously with LSST; he’ll be able to find his targets and pull data collected by the telescope.

“LSST will improve our understanding of small body populations,” Mommert said. “Asteroids, comets, active asteroids, everything that is out there.”

Tales from the Outer Solar System

Kat Volk of the University of Arizona focuses her research on objects in the outer solar system. Pluto, Eris, and other far-out objects have been discovered by comparing photos of an area of sky and looking for something that moved. In fact, Pluto was the first object discovered in this way.

There are about 2,000 known objects in the Kuiper Belt. That’s about how many asteroids we knew of a century ago.

“Kuiper Belt science is a hundred years behind Asteroid Belt science because these things are just so much more difficult to find,” Volk said, because they’re far away, faint, and move slowly. “We had to wait until we had digital cameras and computers to process those images.”

Volk said we probably have discovered all of the 10-kilometer asteroids and most of the 1-kilometer ones. They’re easier to spot because they’re brighter, and there’s money for the hunt because of the potential threat asteroids pose to Earth.

“For comparison, the smallest ever observed Kuiper Belt object is 30 kilometers across, very roughly,” Volk said, adding that we only found that one because the Hubble Space Telescope was used to look for another target for the New Horizons mission after it passed Pluto.

“We’re pretty incomplete in terms of our object inventory in the outer solar system,” Volk said. She said LSST will change that.

“They expect 40,000 new Kuiper Belt ojects,” Volk said. “It’s going to be an entirely new era for the Kuiper Belt with a huge playground of new objects to look at.”

“I am realy excited to see what we’re going to find with LSST, and it’s going to completely revamp our idea of the outer solar system.”

A Crash Course in Asteroid Defense

Andy Rivkin of the Johns Hopkins University Applied Physics Laboratory said that even a 20-meter asteroid packs a wallop when it smashes into Earth. That was roughly the size of the Chelyabinsk meteor in 2013.

Doing the math tells us that there should be about 10 million objects of that size zipping around the solar system, but so far we’ve found only around 10 thousand of them. Back in 2005 Congress told NASA to find 90 percent of objects 140 meters or larger.

“LSST is going to be a critical piece in reaching this goal,” Rivkin said, “and we expect that by 2034 about 86 percent of hazardous asteroids will be found.”

So, what do we do when we spot one headed our way? Rivkin said that for really small ones, like Chelyabinsk, and really large ones, the best idea might be duck and cover. There’s not much to be done about something very large, and small ones don’t pose much of a threat. For those in between, a few options are viable. For one, we could try to deflect the asteroid with a nuclear bomb.

“A lot of people are uncomfortable with nuclear explosions in space, for good reason, and so there’s been a lot of interest in having something else that could work,” Rivkin said.

That something else is a kinetic impactor, which is a fancy way of saying we’ll just smash something into the asteroid to change its speed, and therefore its orbit. It’s a fine idea in theory, but we have no idea if it would actually work. Rivkin is involved in a project that will give it a try.

It’s called DART, which is for Double Asteroid Redirection Test. DART is on schedule to launch for the asteroid Didymos in June of 2021, and then crash into its satellite, nicknamed “Didymoon,” in October 2022. Astronomers will watch through ground-based telescopes and see what happens. Rivkin called it a dress rehearsal for the day we might have to do something about an incoming asteroid.

“A dress rehearsal for, needless to say, a performance we hope never to actually stage,” he said, “demonstrating that we could do this, allowing us to pin these computer simulations to something real, allowing us to better understand asteroidal properties, and giving us a lot of science as an ancillary benefit.”

Astronomy on Tap Seattle is organized by graduate students in astronomy at the University of Washington.

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A cosmic perspective with Jill Tarter of SETI

Jill Tarter thinks that Craig Venter and Daniel Cohen may not have been bold enough when they declared in 2004 that the 21st Century would be the century of biology.

Jill Tarter

The SETI Institute’s Jill Tarter spoke recently at the Rose City Astronomers in Portland, Oregon. (Photo: Greg Scheiderer)

“I think the 21st Century is going to be the century of biology on Earth—and beyond,” Tarter declared during a talk at last month’s meeting of the Rose City Astronomers in Portland, Oregon. Tarter, the Bernard M. Oliver Chair for SETI at the SETI Institute and former director of the Center for SETI Research, thinks there are many ways we might find extraterrestrial intelligence. We might discover it through biomarkers or even artifacts in our own solar system. We could assay the atmospheres of exoplanets looking for biosignatures. We could spot alien “work product” such as structures or signs of engineering. We might even export it, traveling to the Moon, Mars, or even other star systems.

“I think life beyond Earth is a good bet in this 21st Century,” Tarter said, “and when you begin to think about that kind of thing, you really have to reorient your point of view, your perspective. You have to start talking about here and now in a different way, a much bigger point of view, a cosmic perspective.”

Tarter feels that our perspective has changed much since the advent of the space age. Photographs like the Apollo 8 Earthrise or “selfies” by Voyager and Cassini have helped make that happen. We’ve also looked far into the past in viewing distant galaxies.

In the time we’ve been involved in SETI, Tarter says there have been two gamechangers: extremeophiles and exoplanets.

Earthrise

Photos from Space, such as Earthrise by astronaut Willam Anders from Apollo 8, have changed our global perspective. (Photo: NASA)

“Extremeophiles are life as we did not know it until a just few decades ago,” she said, “thriving in places that we once thought completely hostile to life, and they are now illuminating the amazing possibilities for life on our own planet by suggesting more potentially habitable real estate within our solar system and out into the cosmos.”

Similarly, this discovery of thousands of exoplanets has given us more places to look for life.

“Today we know that there are more planets than stars in the Milky Way, and that’s a fundamental change in our perspective,” Tarter said. “When I was a student we knew of nine planets—then lost one!—and didn’t know whether planets would be plentiful around other stars.”

“There is more potentially habitable real estate out there than we ever imagined,” she added, stressing the potential. “We have no idea whether any of it is, in fact, inhabited, but that’s what this century is going to tell us.”

Tarter noted that a big assumption of SETI is that since our technology is visible from a distance, that alien technology might be as well. So we’re looking for something engineered, not a natural occurrence of astrophysics.

“Whether or not SETI succeeds with its optical, infrared, radio searches for signals is going to depend on the longevity of technologies,” Tarter explained, “because unless technologies, on average, last for a long time, there are never going to be two technologies close enough in space to detect one another and coeval in time—lined up at the same time in this ten billion year history of the Milky Way galaxy.”

Tarter said that, in 50 years of SETI, we’ve searched an amount of the cosmos that compares to a 12-ounce glass of water out of the total of Earth’s oceans, so it’s not so surprising that we haven’t yet caught a fish. She adds we’ve been limited by our technology.

“We are beginning to build tools that are commensurate with the vast size of this search, and we understand that the ocean is vast and we are still very, very motivated to go and find what might be out there,” Tarter said. The Allen Telescope Array is a big part of that; you can follow the search at setiquest. There are dozens of other instruments that may provide data to help with SETI, and more than a half-dozen on the drawing boards for the next decade or so.

“This is a hard job,” Tarter said. “This is a lot of very difficult technology to get this job done.”

“Whether or not SETI succeeds in the near term, it has another job to do,” Tarter concluded. “Whether or not it ever finds a signal, it has another job to do. And that is holding up a mirror to all of us on this planet and showing us that in that mirror, when compared to something else out there, we are all the same. Talking about SETI, thinking about SETI, listening to talks about SETI, helps to transfer and to encourage this cosmic perspective. It helps to trivialize the differences among us.”

Tarter encouraged everyone to go home and set their discriptions on their social media profiles to “Earthling,” and to start thinking and acting from that perspective.

“SETI is a very good exercise at working globally to solve a problem,” she said, “and there are many problems that we are going to have to solve quickly in the near term, and do so as a global community.”

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