MARK R. WHITTINGTON
Recently, NASA announced that the James Webb Space Telescope has discovered carbon dioxide at a specific location on Europa’s icy surface in a disrupted “chaos terrain” called the Tara Regio. The discovery has great implications for the possibility of life on the moon of Jupiter.
Europa is one of the largest moons in the solar system, featuring an icy surface covering a salty ocean that may contain life. The famous Italian scientist Galileo discovered Europa in January 1610 with his homemade telescope. Europa has already been examined closely by a number of robotic spacecraft, particularly the Galileo probe that orbited Jupiter between 1995 and 2003.
The European Space Agency launched the Jupiter Icy Moons Explorer (JUICE) in April, which is expected to enter Jupiter space in July 2031. NASA is planning to launch the Europa Clipper in October 2024 with a planned arrival at Jupiter in April 2030. It will orbit Jupiter, doing numerous flybys of Europa during its mission.
The presence of carbon dioxide is one more piece of evidence that Europa’s subsurface ocean may be an abode of life. Carbon is the basis of all life on Earth, as NASA notes. Animal life eats carbon and exhales carbon dioxide that is in turn consumed by plants, which expel oxygen in an endless cycle. Carbon is the fourth most abundant element in the universe.
Neither the Europa Clipper nor the Jupiter Icy Moons Explorer is likely to find definitive proof that Europa’s subsurface ocean contains life, but it may confirm that it has the elements necessary for life. These elements include heat, which, because the ocean is shielded from the sun, is provided by a phenomenon called tidal flexing. Jupiter’s gravity stretches and compresses Europa’s icy shell, thus likely generating enough heat to sustain a warm, interior ocean. The tidal flexing also could cycle water and nutrients between the icy shell, the ocean and the rocky interior, creating conditions for life.
NASA has developed a concept for a Europa Lander which, so far, has remained unfunded. The lander would take samples of the ice crust about four inches beneath the surface and then analyze them in an onboard laboratory. The lander would also carry a seismometer that would monitor geologic activity in Europa’s icy crust.
To find direct evidence of life in Europa’s subsurface ocean, NASA or some other space agency would have to find some way to penetrate the icy crust and insert a submersible into the waters below.
Scientists in both the United States and Europe have studied the concept of a Europa Ocean submersible for years. In 2013, a concept was reportedly being developed by a team from NASA’s Jet Propulsion Laboratory and Sweden’s Uppsala University. The submersible would be barely larger than two soda cans. It would drill a small borehole through Europa’s icy crust to pass through and then use tiny thrusters to maneuver around the subsurface ocean. A fiber optic cable would connect the submarine with the Europa Lander on the surface to transmit data and images and to receive commands.
A Europa Lander mission, especially with a submersible component, is likely to be not only difficult and complex but also expensive. The United States is faced with a mind-numbing national debt that makes selling such a mission difficult. Much of NASA’s attention and resources are being taken up by Project Artemis, which will send astronauts back to the moon and, in the fullness of time, to Mars.
Yet, the discovery of life, even microbial life, on another world that evolved separately from life on Earth, would have world-changing consequences. The discovery of extraterrestrial life is a Holy Grail of science, something sought after even before the advent of the space age. Such a breakthrough would be something scientists have often assumed but never been able to prove.
If life can begin on a single, obscure blue planet near the edge of the galaxy and evolve to eventually bring forth human beings capable of sending their machines and themselves across space, it can start and evolve elsewhere. The implications are beyond easy evaluation.
No comments:
Post a Comment