A small team of astronomers have found a new way to ‘see’ the elusive dark matter halos that surround galaxies, with a new technique 10 times more precise than the previous-best method. The work is published in Monthly Notices of the Royal Astronomical Society.
Scientists currently estimate that up to 85% of the mass in the universe is effectively invisible. This ‘dark matter’ cannot be observed directly, because it does not interact with light in the same way as the ordinary matter that makes up stars, planets, and life on Earth.
So how do we measure what cannot be seen? The key is to measure the effect of gravity that the dark matter produces.
Pol Gurri, the PhD student at Swinburne University of Technology who led the new research, explains: “It’s like looking at a flag to try to know how much wind there is. You cannot see the wind, but the flag’s motion tells you how strongly the wind is blowing.”
The new research focuses on an effect called weak gravitational lensing, which is a feature of Einstein’s general theory of relativity. “The dark matter will very slightly distort the image of anything behind it,” says Associate Professor Edward Taylor, who was also involved in the research. “The effect is a bit like reading a newspaper through the base of a wine glass.”
Weak gravitational lensing is already one of the most successful ways to map the dark matter content of the Universe. Now, the Swinburne team has used the ANU 2.3m Telescope in Australia to map how gravitationally lensed galaxies are rotating. “Because we know how stars and gas are supposed to move inside galaxies, we know roughly what that galaxy should look like,” says Gurri. “By measuring how distorted the real galaxy images are, then we can figure out how much dark matter it would take to explain what we see.”
The new research shows how this velocity information enables a much more precise measurement of the lensing effect than is possible using shape alone. “With our new way of seeing the dark matter,” Gurri says, “we hope to get a clearer picture of where the dark matter is, and what role it plays in how galaxies form.”
Future space missions such as NASA’s Nancy Grace Roman Space Telescope and the European Space Agency’s Euclid Space Telescope are designed, in part, to make these kinds of measurements based on the shapes of hundreds of millions of galaxies. “We have shown that we can make a real contribution to these global efforts with a relatively small telescope built in the 1980s, just by thinking about the problem in a different way,” adds Taylor.
First came Aelita: Queen of Mars, a silent film from 1924 about a Russian engineer who moves to the Red Planet and falls in love with its leader. In 2015’s The Martian, Matt Damon fertilizes alien soil with human feces in order to survive his own mission to outer space. Now, in a new Netflix drama called Away, an international team of astronauts leave their families behind for a three-year mission to Mars. During a layover on the moon, their commander, played by Hilary Swank, tells the world: “We will come together now in pursuit of a dream that was once thought impossible. And if we can do this, we can do anything.”
The world has long fantasized about humans setting foot on this arid, rocky, mountainous orb. But the dream has remained just that — a science-fiction fantasy reserved for comic books and Hollywood blockbusters. That may be changing soon.
NASA’s Ingenuity Mars Helicopter
In this illustration, NASA’s Ingenuity Mars Helicopter stands on the Red Planet’s surface as NASA’s Perseverance rover (partially visible on the left) rolls away. Credit: NASA/JPL-Caltech
According to NASA, if technology developments go to plan, a real-life, crewed mission to the Red Planet could be underway as soon as the 2030s. Among those who have advanced the cause? Allysa Tuano, a University of Delaware student who collaborated with NASA scientists on a recent project.
“It is one thing to work with really smart people,” said Tuano, a mechanical engineering major. “It is another thing to work alongside such innovative minds, people who push themselves in ways that are hard to comprehend. Let’s go to Mars? That takes vision and an ability to see the bigger picture, no matter how wild. It is something I hope to develop as I grow up.”
On a Thursday in July, NASA launched a car-sized rover that is set to land on Mars in February — it takes a while to travel nearly 300 million miles. While this planetary exploration device captured all the headlines, it was not the only marvel of engineering to rocket off the face of the Earth that day. Attached to this rover’s belly is an experiment — a four-pound helicopter called Ingenuity.
Helicopter Above Perseverance on Mars
This illustration depicts Mars Helicopter Ingenuity during a test flight on Mars. Ingenuity is being taken to the Red Planet strapped to the belly of the Perseverance rover (seen in the background). Ingenuity, a technology experiment, will be the first aircraft to attempt controlled flight on another planet in 2021. Credit: NASA/JPL-Caltech
Complete with carbon-fiber blades and the ability to charge itself via a solar array, this spider-like contraption, if all goes well, will be the first to test powered, sustained flight in another planet’s atmosphere. The device will lay groundwork for the deployment of a new-and-improved helicopter in Martian airspace, one with higher-tech capabilities. Specifically, scientists are hoping a future iteration of the rotorcraft will one day collect data and capture high-definition images not achievable via satellite or a ground-bound rover. In other words, it will conduct reconnaissance for a human mission to Mars.
Before Ingenuity even took off, NASA scientists were already working on this sequel — a larger, next-generation helicopter that will test data-collection capabilities. In the fall of 2019, as an intern at NASA’s AMES Research Center in Mountain View, California, Tuano created conceptual designs for this project.
“I was expecting to do data processing,” she said. “Now I look back and I think: Wow. They really had an intern developing design concepts. What an amazing opportunity.”
Allysa Tuano
As a NASA intern, Allysa Tuano worked on conceptual designs for a helicopter that will one day collect data on Mars. When she wasn’t conferring with jet propulsion scientists, she explored California’s stellar coastline. Credit: Allysa Tuano
During a leave of absence from her regular studies, Tuano spent her days at the research center doing CAD — computer-aided design work — with a software program called SolidWorks, which allows for 3-D modeling. With this tool, she conducted structural analysis to improve upon the helicopter designs of previous interns, and she came up with her own renderings. (Her classes at UD on solid mechanics and computer-aided design were, she said, “definitely very helpful.”) Tuano’s job was to focus primarily on shape — for instance, she developed options for folding the helicopter up so that it fits inside a lander, or the protective shell that will cushion an impact on Mars.
There are numerous challenges to designing such a rotorcraft for the Red Planet. Because the Martian atmosphere is so thin, the helicopter must be lightweight (around 44 pounds is the target, all scientific instruments included). But it must also be powerful — blades have to spin much faster than they do on Earth. Additionally, the device has to withstand temperatures that dip to minus 130-degrees Fahrenheit, and it needs to be largely autonomous, since radio signals can take 21 minutes to travel all the way from Earth, ruling out any type of joystick operation.
“I learned a great deal about the person I want to become,” Tuano said about facing these challenges. “In college, failure is really terrifying, but with this kind of research, you’re encouraged to try out many different things, because failure is a lesson you can learn from. I have realized how much I want to access and embrace that mentality.”
Showvik Haque
During his time interning at NASA’s AMES Research Center, Showvik Haque analyzed the functionality of the world’s largest wind tunnel, pictured here. It is capable of testing aircraft as large as the Boeing 737. Credit: Showvik Haque
She isn’t the only Blue Hen to have a formative experience at NASA. In the summer of 2019, then-junior Showvik Haque also interned at the AMES Research Center — he worked on a project concerning the world’s largest wind tunnel, used to test aircraft with wingspans up to 100 feet. At the time, Google was building a headquarters directly across from this 80-by-120-foot space, and engineers feared this nearby structure would mess with the tunnel’s functionality. Using CFD, or computational fluid-dynamics software, Haque studied whether or not this would be the case. What he and the team discovered? There would likely be an effect, but one that can be calibrated for.
“I never thought I would get accepted into an internship as sought after as NASA,” said Haque, a 2020 graduate of UD who now works as an engineer for the Boeing Company in Ridley Park, Pennsylvania. “But I want to encourage students to shed their imposter syndrome. Anything is possible if you put yourself out there, if you challenge yourself and if you make yourself open to the best opportunities possible.”
Both former interns agree: Their hard work was worth total immersion in the spirit of imagination and hope that is so central to the NASA mission. This is a place that represents what Haque called “science in its purest form” — it is not about pushing boundaries for the sake of turning a profit but, rather, for the joy of exploration and the promise of discovery.
“One of my biggest regrets is feeling in the past like I don’t have enough experience or like I’m not good enough to approach these sorts of things,” said Tuano, who has since embarked on another high-profile internship doing product development work with Apple. “Even if you don’t feel like you have a shot at something, you should give it a shot. It will truly surprise you what you can accomplish.”
Or, she added, what you’re capable of helping humanity accomplish. Who knows? The next movie or binge-able Netflix show about achieving the impossible on Mars?
It might just be a documentary.
Delaware Space Grant Consortium
These internships were funded by the Delaware Space Grant Consortium, a NASA program administered by UD. The consortium provides tuition assistance and supports educational opportunities for NASA hopefuls in the areas of science, technology, engineering, mathematics and geography.
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