All posts tagged: Interstellar

Could aliens ever visit Earth? An aerospace scientist unpacks the challenges of interstellar spaceflight.

Could aliens ever visit Earth? An aerospace scientist unpacks the challenges of interstellar spaceflight.

Published by Jenni Sidey

This article was originally featured on The Conversation. On May 22, 2026, the Pentagon released a second batch of previously classified photos and videos showing what appear to be unexplained flying objects. These file dumps were the culmination of a process that was set in motion back in July 2023, when a group of government whistleblowers testified before Congress that the U.S. government was secretly in possession of extraterrestrial spacecraft and suspected alien body parts. That congressional hearing marked the beginning of a cultural shift in which UFO reports are increasingly treated as a matter for serious discussion, both within the government and the scientific community. The Pentagon released over 200 previously classified UFO files in May 2026. Image: Department of Defense But is this newfound legitimacy deserved? As an aerospace scientist who studies aircraft and spacecraft design, I approach this question using math, physics and the principles of engineering. To assess the plausibility of alien visitors, it’s necessary to understand the obstacles that an extraterrestrial vessel would need to overcome to reach Earth. The tyranny of distance There is no evidence …

Tiny ‘metajets’ could use light to steer sails for interstellar travel

Tiny ‘metajets’ could use light to steer sails for interstellar travel

Published by skeptic

An artist’s impression of a light sail RICHARD BIZLEY/SCIENCE PHOTO LIBRARY Interstellar travel propelled by light just got one step closer. Light sails, which are huge sheets pushed along by light that bounces off of them, may be the best way to travel enormous distances through space, and now we may have a way to steer them. “We knew already that any light or laser can impart momentum transfer, but now we can control the direction as well,” says Kaushik Kudtarkar at Texas A&M University. He and his colleagues created a tiny device called a metajet that uses refraction of light, not just reflection, to move in more than one direction at once. The device is a material called a metasurface, an extremely thin sheet textured to manipulate light. In this case, the researchers flipped that on its head, using the light to manipulate the metasurface. A series of tiny pillars on the material steers the light that hits it, with the size and pattern of the pillars controlling the strength and direction of the …

Interstellar comet 3I/ATLAS points to a far colder planetary birthplace

Interstellar comet 3I/ATLAS points to a far colder planetary birthplace

Published by Jenni Sidey

The water coming off comet 3I/ATLAS is not just unusual. It is extreme. Astronomers studying the interstellar comet found that its water is packed with an unusually heavy form of hydrogen called deuterium. The levels are far beyond anything measured in comets from our own solar system. That chemical fingerprint points to a birthplace much colder than the one that produced Earth. It is also colder than the places that formed the planets and the icy bodies that still circle the Sun. The result gives researchers one of their clearest looks yet at how different other planetary systems can be. “Our new observations show that the conditions that led to the formation of our solar system are much different from how planetary systems evolved in different parts of our galaxy,” said Luis Salazar Manzano, lead author of the study and a doctoral student in the University of Michigan’s Department of Astronomy. Astronomers studying the interstellar comet found that its water is packed with an unusually heavy form of hydrogen called deuterium. (CREDIT: Hans Anderson, Michigan …

Laser-powered, ‘metajets’ could be the future of interstellar flight

Laser-powered, ‘metajets’ could be the future of interstellar flight

Published by Jenni Sidey

Alpha Centauri sits more than four light-years away, close enough to fascinate generations of dreamers and far enough to make today’s rockets look painfully limited. At current speeds, a trip there would take far longer than a human lifetime, or even many civilizations. A new set of experiments points to a very different idea, one in which light itself does the pushing. Engineers at Texas A&M University have built tiny devices that can be lifted, pushed and steered by laser light without any physical contact. The objects, called metajets, move because their surfaces are carefully structured to redirect light in ways that generate force. In the lab, that force was strong enough to produce not just motion across a surface but controlled movement in three dimensions. The work comes from Dr. Shoufeng Lan, an assistant professor in the J. Mike Walker ’66 Department of Mechanical Engineering, and researchers in his Lab for Advanced Nanophotonics. Their study describes a way to build control into the material itself, rather than relying only on shaping the incoming beam. …

Only antimatter provides the energy we need for interstellar travel

Only antimatter provides the energy we need for interstellar travel

Published by Jenni Sidey

As humanity basks in the aftermath of the unprecedented success of Artemis II, which took humans back to the Moon for the first time in 54 years and brought them farther from Earth than ever before, many of us can’t help but think about grander goals. As a species, we don’t just dream of returning to the Moon, but of heading to places we’ve never been: other planets, other star systems, or even other galaxies. However, there are big problems we have to solve if we ever want to send humans outside of the Solar System: the problems of distance, time, speed, and fuel efficiency. Interstellar distances are huge, even compared to the vast interplanetary distances we encounter in the Solar System. With current rocket technology, it would take hundreds of human lifetimes to reach even the nearest star, and that’s because we’re limited by speed, which is in turn limited by the efficiency of our fuel sources. Chemical-based rockets leverage quite efficient fuel sources, like liquid oxygen and liquid hydrogen, but transform less than …

NASA’s 1977 computers aboard Voyager are still working in interstellar space

NASA’s 1977 computers aboard Voyager are still working in interstellar space

Published by Jenni Sidey

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. As millions around the world watched on smartphones, T.V.s, or in person, Artemis II and its four-person crew burst from the ground on April 1 and successfully began its 10-day journey to the moon. While all eyes were focused on the Orion spacecraft, it’s worth remembering that it takes a small army of humans—and computers—to make these kinds of awe-inspiring journeys possible. And just like everyday tech users, NASA also has to upgrade its systems from time to time, and the one powering Artemis looks nothing like their relic ancestors. That doesn’t necessarily mean those older versions did not work.  Resurfaced footage released by YouTuber Gary Friedman shows some of the sturdy computing hardware that powered Voyager 1 and 2, a pair of spacecraft first launched in 1977 and tasked with taking a trip through our solar system. Incredibly, both of these spacecraft are still functional in deep space, despite relying on vintage hardware older than many of NASA’s …

3I/ATLAS: Interstellar comet has water unlike any in our solar system

3I/ATLAS: Interstellar comet has water unlike any in our solar system

Published by skeptic

3I/ATLAS is pretty strange International Gemini Observatory/NOIRLab/NSF/AURA/B. Bolin The interstellar comet 3I/ATLAS contains water and carbon molecules at levels never before seen in our solar system. This suggests that it formed around an alien star radically different from and much older than the sun. Astronomers have been tracking 3I/ATLAS since it entered our solar system last year – and it is weird. It appears to be packed with far more carbon dioxide and water than almost any other comet we have seen, and early estimates put its age at 8 billion years – almost twice as old as the sun. Now, Martin Cordiner at NASA’s Goddard Space Flight Center in Maryland and his colleagues have found that its levels of deuterium – a form of hydrogen with an extra neutron – are at least 10 times higher than in any comet we have seen before. Deuterium naturally exists in small amounts in Earth’s oceans, but the levels in 3I/ATLAS are more than 40 times higher. “3I/ATLAS continues to astonish us with what it reveals about …

Interstellar Comet 3I/Atlas Has Another Surprise: It’s Full of Alcohol

Interstellar Comet 3I/Atlas Has Another Surprise: It’s Full of Alcohol

Published by skeptic

Comet 3I/Atlas is now heading out of the solar system and into interstellar space, but scientists are still analyzing the data it left behind as it passed through our cosmic neighborhood. A new study, still under review, reveals a surprising detail: The comet is laden with alcohol. Observations from the ALMA telescope in Chile’s Atacama Desert show that the coma of this celestial object is heavily enriched in methanol, a type of alcohol common in fuels and solvents. Although methanol is commonly found in comets in the solar system, 3I/Atlas contained up to four times the typical amount. According to the study, available at arXiv, 3I/Atlas is the second most methanol-rich comet ever measured, behind only the unusual C/2016 R2, discovered 10 years ago. Parallel investigations have also detected high abundances of other organic compounds, such as carbon dioxide, iron, and nitrogen, reinforcing the idea that this object has an out-of-the-ordinary composition. The combination of excess methanol, a carbon dioxide-dominated coma, and other atypical chemical ratios supports the hypothesis that 3I/Atlas formed in an environment …

Interstellar travel is impossible and aliens haven’t visited Earth, physicists say

Interstellar travel is impossible and aliens haven’t visited Earth, physicists say

Published by Jenni Sidey

“There is a silence in the night sky that has bothered me for as long as I can remember.” Richard Feynman’s reflection lingers because it feels personal. The stars look crowded. Common sense whispers that someone else should be out there. Yet the longer physicists examine the universe, the more that silence appears less mysterious and more structural. Intuition evolved for hunting, shelter, and survival. It did not evolve to grasp light years or relativistic energy. “When you take that human intuition and apply it to the scale of the universe, it doesn’t just fail,” Feynman said. “It snaps.” Five constraints shape that quiet: distance, light speed, propulsion physics, biology, and time. Together they form what Feynman described as “absolute walls that prevent civilizations from ever meeting.” These are not temporary engineering gaps. They are consequences of how reality works. Photo of Richard Feynman, taken in 1984 in the woods of the Robert Treat Paine Estate in Waltham, MA. (CREDIT: Tamiko Thiel 1984 / Wikimedia / CC BY-SA 4.0) A Universe That Refuses to Shrink …

Why interstellar travel is impossible and aliens haven’t visited Earth

Why interstellar travel is impossible and aliens haven’t visited Earth

Published by Jenni Sidey

“There is a silence in the night sky that has bothered me for as long as I can remember.” That observation, attributed to American physicist Richard Feynman, captures a tension many people feel when they look up. The sky appears crowded with stars. Intuition suggests someone else should be out there. However, intuition evolved for survival on Earth, not for interpreting cosmic scales. “When you take that human intuition and apply it to the scale of the universe, it doesn’t just fail,” he said. “It snaps.” The deeper you look at physics, the more that silence starts to make sense. Five separate constraints, distance, light speed, energy, biology, and time, combine into what Feynman described as “absolute walls that prevent civilizations from ever meeting.” These are not merely engineering challenges. They arise from the structure of reality itself. Photo of Richard Feynman, taken in 1984 in the woods of the Robert Treat Paine Estate in Waltham, MA. (CREDIT: Tamiko Thiel 1984 / Wikimedia / CC BY-SA 4.0) A Universe Too Large to Cross Carl Sagan …