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The looming quantum apocalypse: What you need to know!
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By NASA
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This NASA Hubble Space Telescope image of NGC 520 offers one example of possible encounter scenarios between our Milky Way and the Andromeda galaxy. NGC 520 is the product of a collision between two disk galaxies that started 300 million years ago. Credits:
NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and B. Whitmore (STScI) As far back as 1912, astronomers realized that the Andromeda galaxy — then thought to be only a nebula — was headed our way. A century later, astronomers using NASA’s Hubble Space Telescope were able to measure the sideways motion of Andromeda and found it was so negligible that an eventual head-on collision with the Milky Way seemed almost certain.
A smashup between our own galaxy and Andromeda would trigger a firestorm of star birth, supernovae, and maybe toss our Sun into a different orbit. Simulations had suggested it was as inevitable as, in the words of Benjamin Franklin, “death and taxes.”
But now a new study using data from Hubble and the European Space Agency’s (ESA) Gaia space telescope says “not so fast.” Researchers combining observations from the two space observatories re-examined the long-held prediction of a Milky Way – Andromeda collision, and found it is far less inevitable than astronomers had previously suspected.
“We have the most comprehensive study of this problem today that actually folds in all the observational uncertainties,” said Till Sawala, astronomer at the University of Helsinki in Finland and lead author of the study, which appears today in the journal Nature Astronomy.
His team includes researchers at Durham University, United Kingdom; the University of Toulouse, France; and the University of Western Australia. They found that there is approximately a 50-50 chance of the two galaxies colliding within the next 10 billion years. They based this conclusion on computer simulations using the latest observational data.
These galaxy images illustrate three possible encounter scenarios between our Milky Way and the neighboring Andromeda galaxy. Top left: Galaxies M81 and M82. Top right: NGC 6786, a pair of interacting galaxies. Bottom: NGC 520, two merging galaxies. Science: NASA, ESA, STScI, DSS, Till Sawala (University of Helsinki); Image Processing: Joseph DePasquale (STScI) Sawala emphasized that predicting the long-term future of galaxy interactions is highly uncertain, but the new findings challenge the previous consensus and suggest the fate of the Milky Way remains an open question.
“Even using the latest and most precise observational data available, the future of the Local Group of several dozen galaxies is uncertain. Intriguingly, we find an almost equal probability for the widely publicized merger scenario, or, conversely, an alternative one where the Milky Way and Andromeda survive unscathed,” said Sawala.
The collision of the two galaxies had seemed much more likely in 2012, when astronomers Roeland van der Marel and Tony Sohn of the Space Telescope Science Institute in Baltimore, Maryland published a detailed analysis of Hubble observations over a five-to-seven-year period, indicating a direct impact in no more than 5 billion years.
“It’s somewhat ironic that, despite the addition of more precise Hubble data taken in recent years, we are now less certain about the outcome of a potential collision. That’s because of the more complex analysis and because we consider a more complete system. But the only way to get to a new prediction about the eventual fate of the Milky Way will be with even better data,” said Sawala.
100,000 Crash-Dummy Simulations
Astronomers considered 22 different variables that could affect the potential collision between our galaxy and our neighbor, and ran 100,000 simulations called Monte Carlo simulations stretching to 10 billion years into the future.
“Because there are so many variables that each have their errors, that accumulates to rather large uncertainty about the outcome, leading to the conclusion that the chance of a direct collision is only 50% within the next 10 billion years,” said Sawala.
“The Milky Way and Andromeda alone would remain in the same plane as they orbit each other, but this doesn’t mean they need to crash. They could still go past each other,” said Sawala.
Researchers also considered the effects of the orbits of Andromeda’s large satellite galaxy, M33, and a satellite galaxy of the Milky Way called the Large Magellanic Cloud (LMC).
“The extra mass of Andromeda’s satellite galaxy M33 pulls the Milky Way a little bit more towards it. However, we also show that the LMC pulls the Milky Way off the orbital plane and away from Andromeda. It doesn’t mean that the LMC will save us from that merger, but it makes it a bit less likely,” said Sawala.
In about half of the simulations, the two main galaxies fly past each other separated by around half a million light-years or less (five times the Milky Way’s diameter). They move outward but then come back and eventually merge in the far future. The gradual decay of the orbit is caused by a process called dynamical friction between the vast dark-matter halos that surround each galaxy at the beginning.
In most of the other cases, the galaxies don’t even come close enough for dynamical friction to work effectively. In this case, the two galaxies can continue their orbital waltz for a very long time.
The new result also still leaves a small chance of around 2% for a head-on collision between the galaxies in only 4 to 5 billion years. Considering that the warming Sun makes Earth uninhabitable in roughly 1 billion years, and the Sun itself will likely burn out in 5 billion years, a collision with Andromeda is the least of our cosmic worries.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
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Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem (2025)
Hubble Shows Milky Way is Destined for Head-on Collision with Andromeda Galaxy (2012)
Galaxy Details and Mergers
Hubble Traces Hidden History of Andromeda Galaxy (2025)
Hubble’s High-Definition Panoramic View of the Andromeda Galaxy (2015)
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Milky Way and Andromeda Encounters
This selection of images of external galaxies illustrates three encounter scenarios between our Milky Way and the neighboring Andromeda galaxy. Top left: Galaxies M81 and M82. Top right: NGC 6786, a pair of interacting galaxies. Bottom: NGC 520, two merging galaxies.
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Last Updated Jun 02, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center
Contact Media Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute
Baltimore, Maryland
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By NASA
6 min read
Quantum Sensing via Matter-Wave Interferometry Aboard the International Space Station
Future space missions could use quantum technologies to help us understand the physical laws that govern the universe, explore the composition of other planets and their moons, gain insights into unexplained cosmological phenomena, or monitor ice sheet thickness and the amount of water in underground aquafers on Earth.
Upgraded hardware being prepared at Jet Propulsion Lab for launch and install into the Cold Atom Lab on the International Space Station. The Science Module in the background enables CAL researchers to conduct atom interferometry research in Earth’s orbit. Credit: NASA/JPL-Caltech NASA’s Cold Atom Lab (CAL), a first-of-its-kind facility aboard the International Space Station, has performed a series of trailblazing experiments based on the quantum properties of ultracold atoms. The tool used to perform these experiments is called an atom interferometer, and it can precisely measure gravity, magnetic fields, and other forces.
Atom interferometers are currently being used on Earth to study the fundamental nature of gravity and are also being developed to aid aircraft and ship navigation, but use of an atom interferometer in space will enable innovative science capabilities.
Physicists have been eager to apply atom interferometry in space, both to enable new measurements for space science and to capitalize on the extended free-fall conditions found in space. This could enable researchers to achieve unprecedented performance from these quantum sensors.
These interferometers, however, require exquisitely sensitive equipment, and they were previously considered too fragile to function for extended periods without hands-on attention. The Cold Atom Lab, which is operated remotely from Earth, has now demonstrated that it is possible to conduct atom interferometry in space. The CAL Science Team has published two papers so far documenting these experimental milestones.
Depiction of the atom interferometer (AI) setup onboard the ISS in CAL (on the right), showing the interior components of the instrument, and the path of a retro-reflected laser beam (red) inside the vacuum system. The expanded image on the left shows the beam entering the vacuum chamber through a window and between pairs of traces on the atom chip, which are used to confine and cool the atoms to ultracold temperatures. Credit: NASA/JPL-Caltech The results of the first study, published in the November 2023 issue of Nature, described the demonstration of simultaneous atom interferometry with both rubidium and potassium quantum gases for the first time in space. The dual-species atom interferometer not only exhibited robust and repeatable operation of atom interferometry in Earth orbit, but it also served as a pathfinder for future experiments that aim to use quantum gases to test the universality of free fall, a key tenet of Einstein’s theory of general relativity.
In the second study, the results of which were featured in the August 2024 issue of Nature Communications, members of the science team used the CAL atom interferometer to measure subtle vibrations of the space station and to remotely measure the frequency of the atom interferometer laser— the first time ultra-cold atoms have been used to detect changes in the surrounding environment in space. This paper also reported on the demonstration of the wave-like nature of matter persisting for the longest ever freefall time (over a tenth of a second) in space.
“Reaching these milestones was incredibly challenging, and our success was not always a given,” said Jason Williams, the Cold Atom Lab project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It took dedication and a sense of adventure by the team to make this happen.”
Space-based sensors that can measure gravity with high precision have a wide range of potential applications. They could reveal the composition of planets and moons in our solar system, because different materials have different densities that create subtle variations in gravity.
The U.S.-German GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) mission is currently collecting gravity measurements using classical sensors that detect slight changes in gravity to track the movement of water and ice on Earth. A future mission using atom interferometry could provide better precision and stability, revealing even more detail about surface mass changes.
Precise measurements of gravity could also offer insights into the nature of dark matter and dark energy, two major cosmological mysteries. Dark matter is an invisible substance that makes up about 27% of the universe, while the “regular” matter that composes planets, stars, and everything else we can see makes up only 5%. Dark energy makes up the remaining 68% of the universe and is the driver of the universe’s accelerating expansion.
“Atom interferometry could also be used to test Einstein’s theory of general relativity in new ways,” said University of Virginia professor Cass Sackett, a Cold Atom Lab principal investigator. “This is the basic theory explaining the large-scale structure of our universe, and we know that there are aspects of the theory that we don’t understand correctly. This technology may help us fill in those gaps and give us a more complete picture of the reality we inhabit.”
About the size of a minifridge, the Cold Atom Lab launched to the space station in 2018 with the goal of advancing quantum science by placing a long-term facility in the microgravity environment of low Earth orbit. The lab cools atoms to almost absolute zero, or minus 459 degrees Fahrenheit (minus 273 degrees Celsius). At this temperature, some atoms can form a Bose-Einstein condensate, a state of matter in which all atoms essentially share the same quantum identity. As a result, some of the atoms’ typically microscopic quantum properties become macroscopic, making them easier to study.
Quantum properties can sometimes cause atoms to act like solid objects and sometimes like waves. Scientists don’t yet entirely understand how the building blocks of matter can transition between such different physical behaviors, but they’re using quantum technology like what’s available on the Cold Atom Lab to seek answers.
In microgravity, Bose-Einstein condensates can reach colder temperatures and can exist for longer, giving scientists more opportunities to study them. The atom interferometer is among several tools in the CAL facility enabling precision measurements by harnessing the quantum nature of atoms.
Dual-species atom interferometry in space. (Left) Normalized population for ultracold gases of potassium (blue) and rubidium (red) in one of two output states following a simultaneous dual-species atom interferometry sequence. (Right) Correlations observed in the relative population of potassium and rubidium output states. Credit: NASA/JPL-Caltech Due to its wave-like behavior, a single atom can simultaneously travel two physically separate paths. If gravity or other forces are acting on those waves, scientists can measure that influence by observing how the waves recombine and interact.
“I expect that space-based atom interferometry will lead to exciting new discoveries, fantastic quantum technologies impacting everyday life, and will transport us into a quantum future,” said Nick Bigelow, a professor at University of Rochester in New York and Cold Atom Lab principal investigator for a consortium of U.S. and German scientists who co-authored the studies cited above.
Designed and built at the NASA Jet Propulsion Laboratory, Cold Atom Lab is sponsored by the Biological and Physical Sciences (BPS) Division of NASA’s Science Mission Directorate at the Agency’s headquarters in Washington DC and the International Space Station Program at NASA’s Johnson Space Center in Houston, Texas. The work carried out at the Jet Propulsion Laboratory, California Institute of Technology, was executed under a contract with the National Aeronautics and Space Administration.
Learn more about Cold Atom Lab at https://coldatomlab.jpl.nasa.gov/
Just how cold are the atoms in Cold Atom Lab? Find out at https://www.jpl.nasa.gov/news/news.php?feature=7311
To learn more about the Cold Atom Lab’s recent upgrades visit https://www.jpl.nasa.gov/news/upgrading-the-space-stations-cold-atom-lab-with-mixed-reality and https://www.jpl.nasa.gov/news/news.php?feature=7660
Project Lead: Kamal Oudrhiri, Jet Propulsion Laboratory, California Institute of Technology
Sponsoring Organization: Biological and Physical Sciences Division (BPS)
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Last Updated May 06, 2025 Related Terms
Technology Highlights Biological & Physical Sciences Cold Atom Laboratory (CAL) GRACE-FO (Gravity Recovery and Climate Experiment Follow-on) Science-enabling Technology View the full article
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By NASA
Researchers from NASA’s Jet Propulsion Laboratory in Southern California, private companies, and academic institutions are developing the first space-based quantum sensor for measuring gravity. Supported by NASA’s Earth Science Technology Office (ESTO), this mission will mark a first for quantum sensing and will pave the way for groundbreaking observations of everything from petroleum reserves to global supplies of fresh water.
A map of Earth’s gravity. Red indicates areas of the world that exert greater gravitational pull, while blue indicates areas that exert less. A science-grade quantum gravity gradiometer could one day make maps like this with unprecedented accuracy. Image Credit: NASA Earth’s gravitational field is dynamic, changing each day as geologic processes redistribute mass across our planet’s surface. The greater the mass, the greater the gravity.
You wouldn’t notice these subtle changes in gravity as you go about your day, but with sensitive tools called gravity gradiometers, scientists can map the nuances of Earth’s gravitational field and correlate them to subterranean features like aquifers and mineral deposits. These gravity maps are essential for navigation, resource management, and national security.
“We could determine the mass of the Himalayas using atoms,” said Jason Hyon, chief technologist for Earth Science at JPL and director of JPL’s Quantum Space Innovation Center. Hyon and colleagues laid out the concepts behind their Quantum Gravity Gradiometer Pathfinder (QGGPf) instrument in a recent paper in EPJ Quantum Technology.
Gravity gradiometers track how fast an object in one location falls compared to an object falling just a short distance away. The difference in acceleration between these two free-falling objects, also known as test masses, corresponds to differences in gravitational strength. Test masses fall faster where gravity is stronger.
QGGPf will use two clouds of ultra-cold rubidium atoms as test masses. Cooled to a temperature near absolute zero, the particles in these clouds behave like waves. The quantum gravity gradiometer will measure the difference in acceleration between these matter waves to locate gravitational anomalies.
Using clouds of ultra-cold atoms as test masses is ideal for ensuring that space-based gravity measurements remain accurate over long periods of time, explained Sheng-wey Chiow, an experimental physicist at JPL. “With atoms, I can guarantee that every measurement will be the same. We are less sensitive to environmental effects.”
Using atoms as test masses also makes it possible to measure gravity with a compact instrument aboard a single spacecraft. QGGPf will be around 0.3 cubic yards (0.25 cubic meters) in volume and weigh only about 275 pounds (125 kilograms), smaller and lighter than traditional space-based gravity instruments.
Quantum sensors also have the potential for increased sensitivity. By some estimates, a science-grade quantum gravity gradiometer instrument could be as much as ten times more sensitive at measuring gravity than classical sensors.
The main purpose of this technology validation mission, scheduled to launch near the end of the decade, will be to test a collection of novel technologies for manipulating interactions between light and matter at the atomic scale.
“No one has tried to fly one of these instruments yet,” said Ben Stray, a postdoctoral researcher at JPL. “We need to fly it so that we can figure out how well it will operate, and that will allow us to not only advance the quantum gravity gradiometer, but also quantum technology in general.”
This technology development project involves significant collaborations between NASA and small businesses. The team at JPL is working with AOSense and Infleqtion to advance the sensor head technology, while NASA’s Goddard Space Flight Center in Greenbelt, Maryland is working with Vector Atomic to advance the laser optical system.
Ultimately, the innovations achieved during this pathfinder mission could enhance our ability to study Earth, and our ability to understand distant planets and the role gravity plays in shaping the cosmos. “The QGGPf instrument will lead to planetary science applications and fundamental physics applications,” said Hyon.
To learn more about ESTO visit: https://esto.nasa.gov
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Last Updated Apr 15, 2025 Editor NASA Science Editorial Team Contact Gage Taylor gage.taylor@nasa.gov Location NASA Goddard Space Flight Center Related Terms
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