Those twin spacecraft that are searching the universe for signs of life — Dawn and Venera — aren’t the only ones out there. Scientists with NASA’s Astrobiology Program are even working on new satellite missions to look for planets outside our solar system. Unfortunately, none of these probes have been officially approved by NASA.
“As we look for new life in the universe, we need to make sure we know we can do it,” said Marcia McNutt, a former NASA chief scientist and founding director of the Astrobiology Program. McNutt is also the editor of the new The Planetary Society’s publication, Planetary Frontier. A team of researchers working on a $400 million NASA project, which is entering its final stage of development, sought to make the case for the mission at a meeting in the journal Science.
McNutt, who is not on the team, said the mission could help provide insight about how planets form and assemble. Scientists think these moon-sized rocky worlds are composed of a lava disk, or cloud of molten material that’s lined up vertically, because it’s easier to place something there. But the relationship between this disk and the solar system’s rocky planets is still unclear.
This theory of forming the planet around the sun by building a more Earth-like world near the stellar center also holds for moons orbiting giant planets in the solar system. But, because we only have two examples of this theory for the huge Jupiter and Saturn worlds, scientists are left scratching their heads. To find a third kind of solar system satellite, scientists need to work out how to study binary worlds — planet-sized worlds orbiting in separate orbits of smaller, less massive celestial bodies — which could help them make new models.
One of the team’s proposals is to send a satellite to the gas giant Neptune’s moon Triton. The moon, now more than 3,700 feet across, is eight times larger than Earth’s moon.
But this project won’t happen anytime soon. The team is currently working to get the spacecraft ready to launch in 2023, so NASA needs to greenlight the mission by the end of this year or next year.
The authors also presented a number of proposals at the meeting, which are still in progress, but don’t involve spacecraft at all. The group wants to study dark matter, which is an invisible, dense slurry of particles that’s believed to make up at least 80 percent of the universe’s mass. Scientists haven’t been able to study it, but they know it exists because it produces gravitational waves — ripples in space-time.
These ripples are created when matter gathers around a black hole and forms a disk around it. A team of astronomers in Serbia want to study the distribution of dark matter around stars. The heavy dark matter may not be as detectable as its lighter cousin, but it is more insular, which allows researchers to look at more nearby stars.
Finally, other research proposals include exploring the universe’s oceans in the hopes of finding signs of life. Scientists want to take a closer look at a unique feature in the spectrum — light signals that differ between near and far. Some are known as MSTs, which don’t produce a steady stream of light that should be expected from ocean water.
Sometimes scientists fail to think beyond their own devices and become trapped in research that’s static, McNutt said. In these cases, it’s important to do the unexpected. For example, University of Arizona researcher Julie Ostrom led a group that discovered that molecules in the ocean revealed signals of water itself as well as aspects of the ocean that had never been seen. These molecules give us clues about ocean circulation and how fish can become trapped in certain areas.
On Earth, these molecules don’t know how to get out. However, light spectroscopy and detector technology found a way to isolate the trapped biological molecules from the ocean light signal.
“The field has not tried to touch MSTs before, so they have not been investigated on planets with a thin carbon atmosphere like Earth,” McNutt said. “With the new instruments, we can take a fresh look. We’ll see if we can find the life signals while we immerse other MSTs in the ocean water.”
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