image title

Does our solar system have an undiscovered planet? You can help astronomers find out

Astronomers put out the call to citizen scientists to help in search for planet.
February 15, 2017

ASU's Adam Schneider and colleagues are hunting for runaway worlds that may be lurking in the space between stars

Arizona State University astronomer Adam Schneider and his colleagues are hunting for an elusive object lost in space between our sun and the nearest stars. They are asking for your help in the search, using a new citizen-science website called Backyard Worlds: Planet 9.

Astronomers have found evidence for a ninth planet in our solar system. The evidence comes from studying the orbits of objects in the solar system’s Kuiper Belt. This is a zone of comet-like bodies orbiting the sun out beyond the orbit of Neptune. The Kuiper Belt is similar to the asteroid belt that circles the sun between Mars and Jupiter, but it lies dozens of times farther out.

This hypothetical Planet 9 could be similar in size to Neptune, but it may orbit up to a thousand times farther away from the sun than the Earth does. So while astronomers can see its effects on the Kuiper Belt objects, no one has yet observed Planet 9 directly.

"If it exists, Planet 9 could be large — maybe 10 times the mass of Earth but orbiting far out beyond the Kuiper Belt," Schneider said. "Yet it must be extremely dim and hard to find."

A postdoctoral researcher in ASU's School of Earth and Space Exploration, Schneider is particularly interested in studying objects smaller than fully fledged stars and ranging down in size to planets.

Hiding out in the neighborhood

In addition to searching for a distant planet orbiting the sun, this new project will help astronomers identify the sun’s nearest neighbors outside of our solar system.

"There are just over four light-years between Neptune and Proxima Centauri, the nearest star, and much of this vast territory is unexplored," said the lead researcher for Backyard Worlds: Planet 9, Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center.

Astronomers expect the sun's neighborhood will contain many low-mass objects called brown dwarfs. These emit very little light at visible wavelengths, but instead glow dimly with infrared — heat — radiation.

This diagram shows the orbits of several Kuiper Belt objects that were used to infer the existence of Planet 9. If it exists, Planet 9 may reveal itself in WISE infrared images.

"Brown dwarfs are somewhat mysterious," said Schneider. "They have masses of less than 80 times that of Jupiter, because that's the point at which nuclear fusion begins and an object becomes by definition a star." But there's no real lower limit to how small a brown dwarf could be, he said.

"If we find one that's, say, five times the mass of Jupiter and it's orbiting a star, we'd call it a planet," Schneider explained. "But an identical object could also be floating freely in space, unattached to any star, and we'd call it a brown dwarf."

Backyard Worlds: Planet 9

So how do astronomers find such objects in space? That's where you can contribute using a website that enlists the help of citizen scientists. It's called Backyard Worlds: Planet 9, and it uses images taken by NASA's WISE space telescope.

WISE, which stands for Wide-field Infrared Survey Explorer, was launched in late 2009 and has mapped the entire sky several times during the past seven years. WISE detects infrared light, the kind of light emitted by objects at room temperature, like planets and brown dwarfs. This sensitivity to infrared light makes WISE uniquely suited for discovering Planet 9, if it exists.

But there's a snag: Images from WISE have captured nearly 750 million individual sources in the sky. Doubtlessly among these lurk the elusive brown dwarfs and possibly Planet 9. The question is how to sift through the data and identify them.

The trick to finding these needles in haystacks of WISE data is to look for something in motion. Planetary objects and brown dwarfs roaming near the sun can appear to move across the sky, leaving other celestial objects such as background stars and galaxies, which lie immensely far away, apparently fixed in place.

So the best hope for discovering these worlds is to systematically scan infrared images of the sky, searching for objects that move.

Above: Previously known brown dwarf WISE 0855-0714 is seen here in this Backyard World flipbook as a moving orange dot at upper left. Citizen scientists will be asked to inspect images just like this to search for new objects in the solar neighborhood. Photo courtesy of NASA

 

Automated searches for moving objects in the WISE data have already proven successful, but computerized searches are often overwhelmed by image artifacts — visual noise — especially in crowded parts of the sky.

As Schneider explained, "People who join in the Backyard Worlds search bring a unique skill to the search: the human ability to recognize movement."

If it moves, check it out

The search method is a 21st-century version of the same technique used at Arizona's Lowell Observatory by astronomer Clyde Tombaugh. He discovered dwarf planet Pluto 87 years ago this week, on Feb. 18, 1930. Back then, Tombaugh compared two photographs taken a couple weeks apart, looking for a tiny dot of light that shifted position.

The Backyard Worlds search works similarly, but by electronically serving up flipbooks of WISE images taken at different times. As each flipbook plays, objects in the field move or change appearance, making it easy for volunteer observers to flag suspicious objects for later follow-up. Participants will share credit for their discoveries in any scientific publications that results from the project.

The discovery of a ninth planet in our solar system or a new nearest neighbor to the sun would mark a major event in the history of astronomy. Such objects could already be present within the vast WISE dataset, just waiting to be found.

"This program offers an excellent opportunity for citizen scientists to help astronomers with an edge-of-discovery search," said Schneider.

Besides Arizona State University, Backyard Worlds: Planet 9 is a collaboration between NASA, University of California Berkeley, American Museum of Natural History in New York, the Space Telescope Science Institute in Baltimore, and the Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the internet.

 

Top image: This artist's concept illustrates a close-up view of a cool brown dwarf. Objects like this, drifting just beyond our solar system, have been imaged by NASA's Wide-field Infrared Survey Explorer, and many more could be discovered by Backyard Worlds: Planet 9. Image by NASA

Robert Burnham

Science writer , School of Earth and Space Exploration

480-458-8207

 
image title
Disciplines include psychology, sociology, politics, anthropology, archeology.
February 16, 2017

Cooperation and Conflict Symposium brings experts from around the world to discuss the many and varied forms of foul play

The guy at work who contributes squat to a team project. The one who develops alligator arms every time the check arrives. The people you’ve had for dinner 20 times who always show up empty-handed.

Does it make you feel any better that ants, bees and wasps suffer from similar company?

Arizona State University’s first Cooperation and Conflict Symposium was held Thursday, bringing scholars from around campus and the world to discuss “Solving the problem of cheating in large-scale cooperative systems.”

The symposium’s scientists peered through the lens of different disciplines to see how the problem of cheating is addressed, and how cheating is detected, controlled and eliminated.

The event was the brainchild of Athena Aktipis, an assistant professor in the Department of Psychology, and Michael Hechter, a Foundation Professor in the School of Politics and Global Studies. The idea for the symposium began when Aktipis and Hechter started talking about how if you look at how lots of different social organizations work — everything from groups of humans to groups of cells interacting — there are some principles and ideas that apply across all these systems.

“All of these systems have in common that social interactions are happening among the individuals that make them up,” Aktipis said. “We tend to think of social interactions as something that humans do, but it’s actually something that happens across lots of different scales of life. … Cells also have social interaction. They send signals, they respond to signals, they change their behavior and what they’re expressing based on inputs from each other. So sociality is everywhere.”

And so is cheating and the risk of being exploited. That tension exists across all systems, whether human, cell or animal.

“So the idea for the symposium was to see if we could learn about how cheating is limited by looking across lots of systems,” Aktipis said.

Assistant professor Joe Blattman
ASU School of Life Sciences assistant professor Joe Blattman explains his quantitative analysis of viruses and their roles as cheaters or parasites at the ASU Cooperation and Conflict Symposium on Thursday. Twenty speakers from the U.S. and Europe spoke to around 50 people and a live-streaming audience about solving the problem of cheating in large-scale cooperative systems. Photo by Charlie Leight/ASU Now

Speakers came from across a wide array of disciplines, including a psychologist, sociologists, political scientists, anthropologists, immunologists, an archaeologist and an emergency medical doctor.

“We’re all over the map in terms of disciplines, but we’re all focusing on the same problem, which is how to get large-scale cooperation to be viable across multiple systems and how to limit cheating,” Aktipis said.

Are there general principles underlying cooperation?

When you go from small-scale cooperation to large-scale cooperation, cheating increases.

Vampire bats, social insects and people living pastoral lifestyles all share in times of need.

“It doesn’t always work perfectly,” Aktipis said. Cancer, for example, is multicellular cheating; it avoids cell death, monopolizes resources and shrinks the labor pool.

“What this means is you need cheater-detection systems in cellular societies,” she said.

Multicellular bodies detect cheating with an alarm system. At the cellular level, it monitors things like DNA damage. Neighborhood monitoring tracks cell adhesion and architecture. System-wide surveillance eyeballs regions with abnormal proliferation, resource use and waste production.

“As we look at one system and compare it to another … what are the general principles?” Aktipis asked.

Lee Cronk, an anthropology professor at Rutgers University, discussed coordination strategies. Walking up and down a sidewalk without bumping into anyone is a coordination strategy.

Two things interfere with cooperation, according to Cronk: free riders and problems where no one can benefit from cheating. The classic example of the latter is the prisoner’s dilemma, a game that shows why two completely "rational" individuals might not cooperate, even if it appears that it is in their best interests to do so. 

“If you can find a way to get both parties to understand,” that is the best coordination strategy, Cronk said. Coordination can happen on large scales, he said. He cited international trade as an example. “It’s happening on a planet-wide scale,” he said.

But does it eliminate cheating? No. Swindlers, gamblers and others will always cheat.

Oliver Scott Curry, an anthropologist from Oxford, discussed “Bastards, Deviants, Rebels and Scumbags: Other types of cooperation and defection.”

“The main point I want to make this morning is that there are many different types of cooperation,” Scott Curry said. “There are also many types of bad guys.”

The good news is humans are adept at detecting bastards and deviants. These are ancient problems, not new problems. One way to solve cheating is by conditional cooperation, colloquially known as “tit for tat.”

“Life is full of these types of problems,” Scott Curry said.

Regardless of field, the same fundamental problems arise that could benefit from interdisciplinary collaboration.

“Things like cells interacting are going to have different mechanisms compared to how humans interact,” Aktipis said. “But some of the fundamental interactions can be parallel, which means there’s an opportunity to learn from each other, to gain insight into the work each of us is doing. When we start getting synergies in terms of understating the fundamental architecture of how these systems work, each discipline is much more empowered to make an impact because they’re leveraging the strengths from other disciplines as well.”

Written by Emma Greguska and Scott Seckel/ASU Now

 

Top photo: University of Maryland biology professor Gerald Wilkinson asks a question to ASU's Joe Blattman following his talk about viruses and their roles as cheaters or parasites, at the ASU Cooperation and Conflict Symposium on Thursday. Photo by Charlie Leight/ASU Now