The body of Nicolaus Copernicus, the Polish astronomer who created a model of the universe in which the sun, rather than the Earth, is at its centre, has been reburied in Poland’s Frombork Cathedral after a 200-year search for his grave.
PARIS, France (AFP) — A planet relatively close to Earth may have been discovered for the first time outside our solar system with a liquid ocean that could support life, according to scientists using the James Webb Space Telescope.
More than 5,000 exoplanets have been discovered so far, but only a handful lie in the “Goldilocks zone” — a region not too hot or cold that could support liquid water, a key ingredient for life.
Exoplanet LHS 1140 b is one of the few planets in this habitable zone and has been subjected to extensive scrutiny since it was first discovered in 2017.
It is 48 light years away from Earth, which is the equivalent of more than 450 trillion kilometers (280 trillion miles), a relatively small distance in the vast distances of the universe.
The exoplanet is a small gas giant known as a “mini-Neptune” whose atmosphere is thought to be too dense with hydrogen and helium to support extraterrestrial life.
But new observations from the Webb Telescope confirm that the exoplanet is in fact a rocky “super-Earth.”
The planet is 1.7 times the size of Earth but 5.6 times more massive, according to the study published late Wednesday in the Astrophysical Journal Letters.
The Webb Telescope was able to analyze the planet’s atmosphere as it passed in front of its star.
No signs of hydrogen or helium were found, ruling out the possibility that the planet is a mini-Neptune.
Study co-author Martin Turbé of France’s CNRS scientific research center told AFP that the planet’s density shows “there is indeed a lot of water present.”
It could be a really huge amount of water.
The water in Earth’s oceans makes up just 0.02% of Earth’s mass, but it’s estimated that 10-20% of the mass of exoplanets is water.
Whether this water is liquid or ice depends on the planet’s atmosphere.
“We don’t have direct evidence that it has an atmosphere, but several factors point in that direction,” Tarbet said.
“Of all currently known temperate exoplanets, LHS 1140 b may be our best option for indirectly confirming the presence of liquid water on the surface of an alien world in the future,” said Charles Cadieux, lead author of the study and a doctoral student at the University of Montreal.
On the plus side, the planet is gently warmed by a red dwarf star that’s one-fifth the size of the Sun.
Tarbet said the exoplanet’s surface temperature should be quite similar to that of Earth and Mars.
The presence of gases such as carbon dioxide will play a key role in determining whether a planet is covered in ice or water.
One possibility is that the surface is mostly icy, but that the parts of the planet most exposed to the star’s heat contain vast liquid oceans.
Models suggest that the ocean could be about 4,000 kilometers in diameter, roughly half the surface area of the Atlantic Ocean.
Alternatively, liquid water could be hidden beneath a thick shell of ice, as on the moons Ganymede, Enceladus, and Europa that orbit Jupiter and Saturn.
Webb’s equipment found signs suggesting “the presence of nitrogen,” Cadieux said, adding that further research is needed to confirm the findings.
Nitrogen is found everywhere on Earth and is thought to be a potential building block for life.
The researchers hope to get a few more precious hours of Webb telescope time to study LHS 1140 b in more detail.
The researchers estimate it will take at least a year to determine whether the exoplanet has an atmosphere, and another two to three years to detect the presence of carbon dioxide.
