Can we —and we should—send life to the nearest star?
A new study by scientists explores what it takes to send life to the nearest star. One idea is that tardigrades, or tardigrades, as in the concept in this painting, will be the first beings to leave. These small creatures are only 1 mm (0.04 in.) or smaller in size. Image from the University of California, Santa Barbara.
Sending life to the nearest star?
The first interstellar voyagers may not have been humans. Instead, they may be small creatures, such as tardigrades (aka tardigrades). Or it could be nematodes (aka roundworms), such as Caenorhabditis elegans. These small creatures can sail on miniature wafer ships powered by lasers. It was the idea of a team of scientists who published a paper on these topics in the Peer-Reviewed Journal of Astronautics in January 2022.
Scientists wonder, how can life be delivered to the nearest star?
Destination: [Centaur] Proxima Centauri
Proxima Centauri is the closest star to Earth. But in the vastness of the universe, proximity is only a relative concept. Proxima Centauri is located about 4.22 light-years away, and each light-year is about 6 trillion miles (9 trillion kilometers). Scientists have discovered two planets orbiting Proxima Centauri.
Philip Lubin of the University of California, Santa Barbara, is one of the co-authors of the new study. His research interests are experimental cosmology, that is, the idea of using the entire universe as a laboratory to test physics. He led the Starlight Program at UC Santa Barbara, which was funded by NASA. The Starlight Program is part of NASA's massive directional energy, which can propel small spacecraft to the relativistic speed.
The ultimate goal is to make humanity's first interstellar mission possible. The project was launched in 2009 with initial funding from the University of California, Santa Barbara, and funding from the NASA Space Fund Alliance from NASA to innovate advanced concepts. Nasa has dubbed this effort DEEP-IN (Directed Energy Propulsion for Interstellar Exploration) and DEIS (Interstellar Directed Energy Research).
So Lubin is concerned with the technology needed to reach Proxima Centauri over the length of a person's lifespan. Take the Voyager 1 spacecraft, for example, which has been flying for 44 years and is now about 14 billion miles (22 billion kilometers) from the Sun, outside the solar system, and it is still only 21 light-hours away, while Proxima Centauri is more than 4 light-years away. Using Voyager 1's technology, we need 80,000 years to reach Proxima Centauri.
This is where lasers and wafers come in
Lubin's team at the University of California, Santa Barbara explored the possibility of launching a small space probe powered by light into Proxima Centauri. Put human space travel aside and consider what it takes to transport creatures over long distances in space. Consider using small, hardy creatures. These scientists envision miniature space travelers and spaceships. The small space probes they described in the study would take inferences from laser arrays on Earth or the Moon, pushing them to reach the speed of light by 20 to 30 percent. That's 20-30 percent of the speed of 186,000 miles (300,000 kilometers) per second. Lubin said: "
This is unprecedented, pushing macroscopic objects at nearly the speed of light. It may look like a semiconductor wafer with edges to protect it from radiation and dust as it travels through the interstellar medium. It may be as big as your hand. ”
At such a speed — about 100 million miles (161 million kilometers) per hour — their proposed silicon spacecraft could reach Proxima Centauri in about 20 years, they say.
Passengers on a wafer spacecraft
Nematodes or roundworms, such as Caenorhabditis elegans, are ideal for interstellar flight. Caenorhabditis elegans can go into a state of suspended animation, a useful trick to survive a long flight. These creatures are no strangers to space travel. They have taken the shuttle to the space station several times.
Joel Rothman of the University of California, Santa Barbara, is another co-author of the new paper. Rothman has been studying nematodes for decades. He elaborated on their advantages for space travel: "
When they fly away from Earth at nearly the speed of light, we can tell how well they remember their training behavior and examine their metabolism, physiology, neurological function, reproduction, and aging. ”
Rothman also explained why he was involved in the work: "
I think it's our destiny to keep exploring. Throughout human history, our level of exploration is getting smaller and smaller, and we are exploring at a larger and larger level. This drive for constant exploration is at the heart of ours as a species.
Just as dogs and monkeys paved the way for humans to go into space, studying nematodes and tardigrades in interstellar space may help us understand how humans achieve the same outfit. Rothman said:
We can start thinking about designing interstellar transporters, no matter what animals they are, and design principles in a way that can improve the problems detected on these small animals. ”
Caenorhabditis elegans is the best choice for interstellar travel. Image from Wikipedia.
The moral question behind interstellar travel
Among the scientists involved in the study was a radiologist and a professionally trained theologian.
They believe that creatures that venture through the stars for the first time to a planet around Proxima Centauri will never successfully land and reproduce there. Their mission is simply a journey with no return to determine the feasibility of interstellar travel. These creatures either burn up as soon as they enter the Earth's atmosphere or crash on land.
Anything from Proxima Centauri will not return to Earth, thus avoiding the problem of cross-contamination between Proxima Centauri's planets and our own Earth. "It seems to me that once you start talking about the directional spread of life, this view, often referred to as panspecies, is that life comes from somewhere else and possibly even from another civilization, eventually reaching Earth through comets and other debris, so the idea that we're sending life to other planets does pose a big problem," Rothman said. ”
At this stage, researchers are still pondering this unsolvable problem. Researchers are also pondering other questions: Is it moral to send humans to the stars knowing that they may never be able to return home? And the feasibility of sending small microbes or human DNA?
These are some very tricky questions. But as Rothman points out: It seems to me that we should not and will not suppress the desire inherent in our nature to explore the unknown.
Joel Rothman, director of the Biomolecular Science and Engineering Program at the University of California, Santa Barbara, is a co-author of a paper on sending life to the nearest star. Image credit: UC Santa Barbara.
Philip Lubin specializes in experimental cosmology in the Department of Physics at the University of California, Santa Barbara. He is the co-author of the paper, which considers sending life to the nearest star. Image from the University of California, Santa Barbara.
Brief Overview: A team of researchers studied the idea of sending life to the nearest star. They explored the possibility of the creature taking a wafer boat to Centaurus.
BY：Kelly Kizer Whitt
FY：Astronomical volunteer team
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