“The search for planets is the search for life,”
The “era of the exoplanet” officially began in October 1995, when Nobel laureates Michel Major and Didier Cuelos unveiled the first discovery of a planet outside our solar system, an exoplanet orbiting a solar star in our home galaxy, the Milky Way. 51 Pegasi b, a gaseous ball comparable to Jupiter, the largest gas giant in the solar system. Their discovery started a revolution in astronomy and since then more than 4,100 exoplanets have been discovered in the Milky Way. And strange new worlds are being discovered almost daily.
The “extremely extreme life” of the Milky Way
One of these strange “things” was announced by a team of researchers from Arizona State University (ASU) and the University of Chicago in a new study published in The Planetary Science Journal. The team decided that some carbon-rich exoplanets could, under appropriate circumstances, be made from diamonds and silica. “These exoplanets look like nothing in our solar system,” said lead author Harrison Allen-Sutter of ASU’s School of Earth and Space Research.
When stars and planets form, they do so from the same gas cloud, so their volumetric composition is similar. A star with a lower carbon to oxygen ratio will have planets like Earth, consisting of silicates and oxides with very little diamond content (the diamond content of Earth is about 0.001%).
But exoplanets around stars with a higher carbon to oxygen ratio than our sun are more likely to be rich in carbon. Alan-Sutter and co-authors suggested that these carbon-rich exoplanets could turn into diamond and silicate if water (which is abundant in the universe) was present, creating a diamond-rich composition.
“Island Worlds” – an entirely new frontier of exoplanets
To test this hypothesis, the research team had to mimic the interior of carbide exoplanets using high heat and high pressure. For this purpose, they used cells with diamond anvils under high pressure in the co-author of the laboratory for earth and planetary materials of Shim. First, they immersed silicon carbide in water and compressed the sample between the diamonds to a very high pressure. Then, to observe the reaction between silicon carbide and water, they performed laser heating at the Argonne National Laboratory in Illinois, making X-ray measurements while the laser heated the sample at high pressure.
As they predicted, at high heat and pressure, silicon carbide reacted with water and turned into diamonds and silica.
“Proof of existence”
Some astronomers have said it doesn’t matter if there are other life forms found in the Milky Way or in other galaxies. The fact that we are here provides “proof of existence,” as it is called in mathematics. But for now, the search continues. Planetary scientists and astrobiologists use sophisticated tools in space and on Earth to find planets with the right properties and the right location around their stars where life can exist.
“Neighboring aliens may be in the” Early Earth “phase of life” – Carl Sagan Institute
However, for the carbon-rich planets that are the focus of this study, they probably do not have the properties necessary for life. While the Earth is geologically active (habitability indicator), the results of this study show that carbon-rich planets are too difficult to be geologically active, and this lack of geological activity can make the atmospheric composition uninhabitable. Atmospheres are crucial to life as they provide us with air to breathe, protection from the harsh space environment and even the pressure that liquid water allows.
“Regardless of habitability, this is an additional step that helps us understand and characterize the ever-increasing and improving observations of exoplanets,” says Alan-Suther. “The more we learn, the better we will be able to interpret new data from upcoming future missions such as the James Webb Space Telescope and the Roman Nancy Grace Space Telescope to understand the world beyond our own solar system.”
The daily galaxy, Sam Cabot, through Arizona State University
Image credit: Shutterstock license