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By European Space Agency
Ice melting from glaciers around the world is depleting regional freshwater resources and driving global sea levels to rise at ever-faster rates.
According to new findings, through an international effort involving 35 research teams, glaciers have been losing an average of 273 billion tonnes of ice per year since the year 2000 – but hidden within this average there has been an alarming increase over the last 10 years.
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By NASA
u0022The really interesting thing to me is how time theoretically acts strangely around black holes. According to Albert Einstein’s theory of gravity, black holes change the flow of time,u0022 said Jeremy Schnittman, Goddard research astrophysicist. u0022So much of how we experience the world is based on time, time marching steadily forward. Anything that changes that is a fascinating take on reality.u0022u003cstrongu003eu003cemu003eCredits: NASA’s Goddard Space Flight Center / Rebecca Rothu003c/emu003eu003c/strongu003e Name: Jeremy Schnittman
Formal Job Classification: Research astrophysicist
Organization: Gravitational Astrophysics Laboratory, Astrophysics Division (Code 663)
What do you do and what is most interesting about your role here at Goddard? How do you help support Goddard’s mission?
I try to understand the formation and properties of black holes. I also help develop ideas for new missions to study black holes.
What drew you to astrophysics?
I always liked science and math. The great thing about astrophysics is that it involves a little bit of everything – math, computer programming, physics, chemistry and even philosophy to understand the big picture, the enormity of space.
I have a B.A. in physics from Harvard, and a Ph.D. in physics from MIT. I came to Goddard in 2010 after two post-doctoral fellowships.
Explore how the extreme gravity of two orbiting supermassive black holes distorts our view. In this visualization, disks of bright, hot, churning gas encircle both black holes, shown in red and blue to better track the light source. The red disk orbits the larger black hole, which weighs 200 million times the mass of our Sun, while its smaller blue companion weighs half as much. Zooming into each black hole reveals multiple, increasingly warped images of its partner. Watch to learn more.
Credits: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell
Download high-resolution video and images from NASA’s Scientific Visualization Studio As an astrophysicist, what do you think about?
I think of myself as a computational physicist as opposed to an experimental or observational physicist. I write many computer programs to do computer simulations of black holes. I also do a lot of theoretical physics, which is pencil and paper work. I think a lot about equations and math to understand black holes.
What is most philosophical about black holes to me is not so much what people most often think about, that their gravity is so strong that even light cannot escape. The really interesting thing to me is how time theoretically acts strangely around black holes. According to Albert Einstein’s theory of gravity, black holes change the flow of time. If you could get close enough to a black hole, theoretically you could go back and forth in time. All our experiments and observations seem to indicate that is how black holes might behave.
So much of how we experience the world is based on time, time marching steadily forward. Anything that changes that is a fascinating take on reality.
Related Link: Gravity Assist: Black Hole Mysteries, with Jeremy Schnittman What do you tell the people you mentor?
I mentor undergraduate, graduate, and post graduate students in astrophysics. Since we are working remotely, I have students from all over the country. I help them with their research projects which mostly relate to black holes in some way. I also offer career advice and help them with their work-life balance. When possible, family comes first.
There are more people coming out of graduate school in astrophysics than there are jobs, so there are going to be many people who will not work for NASA or as a professor. Fortunately, there are a lot of other fascinating, related jobs, and I help guide the students there.
What do you do for fun?
I have a woodshop in our basement where I build furniture, dollhouses, toys, and other items for gifts. As a theoretical physicist, I don’t get to work in a lab. So it is nice to have some hands on experience.
I do a lot of hiking and cycling to exercise. I also enjoy spending time with my family.
Who is your favorite author?
Andy Weir is probably my favorite sci-fi author. I also love the epic naval historical fiction by Patrick O’Brian.
Who inspires you?
My childhood hero, who is still my scientific hero, is Albert Einstein. The more I work in astrophysics, the more he impresses me. Every single one of his predictions that we have been able to test has proven true. It may be a while, but someday I hope we prove his theories about time travel.
Also, I admire Kip Thorne, an American physicist from Cal Tech and recent Nobel laureate, who is “the man” when it comes to black holes. He is also a really nice, good guy, a real mensch. Very humble and down-to-earth. He is always extremely patient, kind and encouraging especially to the younger scientists. He is a good role model as I transition from junior to more senior status.
What is your one big dream?
I make a lot of predictions, so it would be exciting if one of my theories was proven correct. Hopefully someday.
By Elizabeth M. Jarrell
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Conversations with Goddard Conversations With Goddard is a collection of question and answer profiles highlighting the breadth and depth of NASA’s Goddard Space Flight Center’s talented and diverse workforce. The Conversations have been published twice a month on average since May 2011. Read past editions on Goddard’s “Our People” webpage.
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Last Updated Feb 10, 2025 Related Terms
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By NASA
NASA’s Dawn spacecraft captured this image of Vesta as it left the giant asteroid’s orbit in 2012. The framing camera was looking down at the north pole, which is in the middle of the image.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Known as flow formations, these channels could be etched on bodies that would seem inhospitable to liquid because they are exposed to the extreme vacuum conditions of space.
Pocked with craters, the surfaces of many celestial bodies in our solar system provide clear evidence of a 4.6-billion-year battering by meteoroids and other space debris. But on some worlds, including the giant asteroid Vesta that NASA’s Dawn mission explored, the surfaces also contain deep channels, or gullies, whose origins are not fully understood.
A prime hypothesis holds that they formed from dry debris flows driven by geophysical processes, such as meteoroid impacts, and changes in temperature due to Sun exposure. A recent NASA-funded study, however, provides some evidence that impacts on Vesta may have triggered a less-obvious geologic process: sudden and brief flows of water that carved gullies and deposited fans of sediment. By using lab equipment to mimic conditions on Vesta, the study, which appeared in Planetary Science Journal, detailed for the first time what the liquid could be made of and how long it would flow before freezing.
Although the existence of frozen brine deposits on Vesta is unconfirmed, scientists have previously hypothesized that meteoroid impacts could have exposed and melted ice that lay under the surface of worlds like Vesta. In that scenario, flows resulting from this process could have etched gullies and other surface features that resemble those on Earth.
To explore potential explanations for deep channels, or gullies, seen on Vesta, scientists used JPL’s Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, to simulate conditions on the giant asteroid that would occur after meteoroids strike the surface.NASA/JPL-Caltech But how could airless worlds — celestial bodies without atmospheres and exposed to the intense vacuum of space — host liquids on the surface long enough for them to flow? Such a process would run contrary to the understanding that liquids quickly destabilize in a vacuum, changing to a gas when the pressure drops.
“Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said project leader and planetary scientist Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California, where the experiments were conducted. “But for how long? Most liquids become unstable quickly on these airless bodies, where the vacuum of space is unyielding.”
The critical component turns out to be sodium chloride — table salt. The experiments found that in conditions like those on Vesta, pure water froze almost instantly, while briny liquids stayed fluid for at least an hour. “That’s long enough to form the flow-associated features identified on Vesta, which were estimated to require up to a half-hour,” said lead author Michael J. Poston of the Southwest Research Institute in San Antonio.
Launched in 2007, the Dawn spacecraft traveled to the main asteroid belt between Mars and Jupiter to orbit Vesta for 14 months and Ceres for almost four years. Before ending in 2018, the mission uncovered evidence that Ceres had been home to a subsurface reservoir of brine and may still be transferring brines from its interior to the surface. The recent research offers insights into processes on Ceres but focuses on Vesta, where ice and salts may produce briny liquid when heated by an impact, scientists said.
Re-creating Vesta
To re-create Vesta-like conditions that would occur after a meteoroid impact, the scientists relied on a test chamber at JPL called the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE. By rapidly reducing the air pressure surrounding samples of liquid, they mimicked the environment around fluid that comes to the surface. Exposed to vacuum conditions, pure water froze instantly. But salty fluids hung around longer, continuing to flow before freezing.
The brines they experimented with were a little over an inch (a few centimeters) deep; scientists concluded the flows on Vesta that are yards to tens of yards deep would take even longer to refreeze.
The researchers were also able to re-create the “lids” of frozen material thought to form on brines. Essentially a frozen top layer, the lids stabilize the liquid beneath them, protecting it from being exposed to the vacuum of space — or, in this case the vacuum of the DUSTIE chamber — and helping the liquid flow longer before freezing again.
This phenomenon is similar to how on Earth lava flows farther in lava tubes than when exposed to cool surface temperatures. It also matches up with modeling research conducted around potential mud volcanoes on Mars and volcanoes that may have spewed icy material from volcanoes on Jupiter’s moon Europa.
“Our results contribute to a growing body of work that uses lab experiments to understand how long liquids last on a variety of worlds,” Scully said.
Find more information about NASA’s Dawn mission here:
https://science.nasa.gov/mission/dawn/
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Jet Propulsion Laboratory, Pasadena, Calif.
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NASA Headquarters, Washington
202-358-1600
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Last Updated Dec 20, 2024 Related Terms
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By NASA
NASA/Michala Garrison, using Landsat data from the U.S. Geological Survey and VIIRS day-night band data from the Suomi National Polar-orbiting Partnership Lava encroaches on the Blue Lagoon, a popular tourist destination in Iceland, in this Nov. 24, 2024, Landsat 9 image overlaid with an infrared signal. The infrared signal helps distinguish the lava’s heat signature.
A volcanic fissure burst open on Iceland’s Reykjanes peninsula four days prior, heralded by a series of earthquakes. A plume of gas, consisting primarily of sulfur dioxide, streamed from the lava. The Reykjanes peninsula eruption is the seventh in a series of events that began in December 2023.
Image credit: NASA/Michala Garrison, using Landsat data from the U.S. Geological Survey and VIIRS day-night band data from the Suomi National Polar-orbiting Partnership
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Coastal locations, such as Drakes Bay on the Point Reyes peninsula in Northern California, are increasingly vulnerable to sea level rise.NOAA/NMFS/WCR/CCO The information will help people who live in coastal areas prepare for impacts caused by rising sea levels.
Earth’s ocean is rising, disrupting livelihoods and infrastructure in coastal communities around the world. Agencies and organizations are working to prepare people as their world changes around them, and NASA information is helping these efforts.
The agency’s global data is now available in the sea level section of the Earth Information Center. NASA developed the global sea level change website in collaboration with the U.S. Department of Defense, the World Bank, the U.S. Department of State, and the United Nations Development Programme.
The site includes information on projected sea level rise through the year 2150 for coastlines around the world, as well as estimates of how much flooding a coastal community or region can expect to see in the next 30 years. The projections come from data collected by NASA and its partners and from computer models of ice sheets and the ocean, as well as the latest sea level assessment from the Intergovernmental Panel on Climate Change, and other sources.
“NASA innovates for the benefit of humanity. Our cutting-edge instruments and data-driven information tools help communities and organizations respond to natural hazards and extreme weather, and inform critical coastal infrastructure planning decisions,” said Karen St. Germain, director of the Earth science division at NASA Headquarters in Washington.
Information to Action
International organizations such as the World Bank will use the data from the global sea level change site for tasks including the creation of Climate Risk Profiles for countries especially vulnerable to sea level rise.
The Defense Department will continue to incorporate sea level rise data into its plans to anticipate and respond to hazards posed to its facilities by the effects of rising oceans. Similarly, the State Department uses the information for activities ranging from disaster preparedness to long-term adaptation planning to supporting partners around the world in related efforts.
“We are at a moment of truth in our fight against the climate crisis. The science is unequivocal and must serve as the bedrock upon which decision-making is built. With many communities around the world already facing severe impacts from sea-level rise, this new resource provides a vital tool to help them protect lives and livelihoods. It also illustrates what is at stake between a 1.5-degree-Celsius world and a current-policies trajectory for all coastal communities worldwide,” said Assistant Secretary-General Selwin Hart, special adviser to the United Nations secretary-general on climate action and just transition.
Rising Faster
NASA-led data analyses have revealed that between 1970 and 2023, 96% of countries with coastlines have experienced sea level rise. The rate of that global rise has also accelerated, more than doubling from 0.08 inches (0.21 centimeters) per year in 1993 to about 0.18 inches (0.45 centimeters) per year in 2023.
As the rate of sea level rise increases, millions of people could face the related effects sooner than previously projected, including larger storm surges, more saltwater intrusion into groundwater, and additional high-tide flood days — also known as nuisance floods or sunny day floods.
“This new platform shows the timing of future floods and the magnitude of rising waters in all coastal countries worldwide, connecting science and physics to impacts on people’s livelihoods and safety,” said Nadya Vinogradova Shiffer, director of the ocean physics program at NASA Headquarters in Washington.
Data released earlier this year found that Pacific Island nations will experience at least 6 inches (15 centimeters) of sea level rise in the next 30 years. The number of high-tide flood days will increase by an order of magnitude for nearly all Pacific Island nations by the 2050s.
“The data is clear: Sea levels are rising around the world, and they’re rising faster and faster,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California and head of the agency’s sea level change science team. “Having the best information to make decisions about how to plan for rising seas is more crucial than ever.”
To explore the global sea level change site:
https://earth.gov/sealevel
News Media Contacts
Karen Fox / Elizabeth Vlock
NASA Headquarters, Washington
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Jet Propulsion Laboratory, Pasadena, Calif.
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Last Updated Nov 13, 2024 Related Terms
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