Every month, the universe reveals its new, never-seen-before colors to us. And the same has been the case with September 2021. Last month, some spectacular astronomical discoveries knocked at our doors, and here, we have compiled a list of some of them!
Hycean worlds: A new class of habitable planets
In one of the most striking discoveries of the month, astronomers found a new class of exoplanets that could host life beyond Earth. Known as Hycean worlds, they are hot, have large oceans, thick hydrogen atmospheres, and are nearly 2.5 times the size of our planet. Because of their size, they fall somewhere between super-Earths and mini-Neptunes and enjoy the properties of both worlds.
However, not all the Hycean worlds are the same. Some orbit so close to their stars that they’re tidally locked. This gives them one scorching hot dayside and one eternally dark night side. On the other hand, some orbit so far away from their host star that they encounter very little stellar radiation. Despite these extreme conditions, Hyceans are expected to be habitable for microbial life. Their oceanic conditions are probably similar to those driving microbial life in Earth’s oceans.
Hycean worlds are good places to search for biosignature gases: oxygen and methane. In the coming years, the James Webb Space Telescope is expected to detect some biomolecules on one of the most promising targets, K2-18b. A biosignature detection can bring a revolution in our understanding of life in the Universe.
A premature supernova triggered by a dead star
In 2017, astronomers observed a particularly luminous and unusual source of radio waves. The observation was made as a part of the Very Large Array (VLA) Sky Survey, and since its observation in 2017, the bright radio flare has amused astronomers. Efforts have been made to identify the source of the flare. And now, a team of astronomers has figured out the reason that led to a bright radio flare. A new study has revealed that it resulted from a catastrophic crash between a black hole or neutron star and the companion star.
Massive stars usually explode as supernovae when they run out of nuclear fuel. But this explosion was different from all the supernovae known to date. Here, an invading black hole or neutron star prematurely triggered its companion star to explode. While going through the data, researchers found an extremely luminous radio source. It appeared that the radio transient occurred when a star exploded in a supernova. However, the timescale of the explosion was a bit unusual. Later, another team analyzed a different catalog of X-ray transients. Analysis showed that the X-rays and the radio waves were likely coming from the same event.
The X-ray transient signaled that a relativistic jet was launched at the time of the explosion. While the radio transient indicated that the material from the explosion later crashed into a massive torus of dense gas ejected from the star centuries earlier. It’s believed that a leftover remnant of a star, either a black hole or a neutron star, was orbiting an active star. Further, the gravitational pull brought the dead star and the active star together and the black hole and the companion star crashed into each other, which prematurely caused the companion star to collapse in on itself and explode into a supernova. This collision created distinct X-ray and radio wave bursts, which had been predicted earlier.
This marks the first-ever confirmation of a merger-triggered supernova.
Astronauts to use their blood, urine, and tears to make concrete on Mars
Colonizing Mars has been on mankind’s wish list for a long time. However, building structures on Mars requires raw materials like concrete, bricks, and others. But, transporting raw materials from Earth to Mars is not a viable option. This means that we need technology to develop raw materials on Mars itself, and a new study has shown that it might be possible to do so. Mars consists of a layer of dirt and rubble on its surface, known as regolith. Experiments have shown that these regoliths can act as viable building materials, and the human body can help in gluing them together.
Earlier studies have found that urea in human urine helps in plasticizing concrete, making it less brittle, more flexible, and eventually harder to better withstand mechanical stresses. Moreover, a material called AstroCrete uses albumin, which is a protein found in human blood plasma, to bind the concrete together. The team used albumin to fabricate extra-terrestrial regolith biocomposites, which had compressive strengths as high as 25 megapascals. Moreover, the addition of urea increased the strength of AstroCrete to up to 39.7 megapascals, in comparison to the ordinary concrete on Earth that has strengths between 20 and 32 megapascals.
The team also tested synthetic spider silk and bovine serum albumin for the same and found that over two years, six humans could donate enough albumin to build 500 kilograms of AstroCrete. However, the long-term health effects of continuous plasma donation in a low-gravity, high-radiation environment are not known so far, and it is not clear that how much plasma can be taken from a single person sustainably.
Although the idea seems to be a short-term solution, with the advancements taking place, it will eventually be superseded by versatile bioreactors and other technologies.
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