Magnetic Field
Dark area across the top of the sun, known as a coronal hole, a region on the sun where the magnetic field is open to interplanetary space, sending coronal material speeding out in what is called a high-speed solar wind stream, is shown in this handout photo taken October 10, 2015 and provided by NASA October 14, 2015. Reuters/NASA

When scientists studied a young, Sun-like star Kappa Ceti, they discovered that magnetic field plays a crucial role in making a planet fit for life. According to them, life on Earth was made possible because of the presence of protective magnetic field. It was definitely one of the most important factors apart from a blanketing atmosphere, liquid water and Earth’s rocky surface.

Kappa Ceti is quite similar to the Sun but much younger. It is situated 30 light years away in the constellation Cetus, the Whale. It is 400-600 million years old (age estimated from rotation period). Interestingly, the time period coincides with the time when life on Earth started.

That is why scientists believe that Kappa Ceti can give invaluable insights into the early history of the solar system. Kappa Ceti is extremely active magnetically. There are numerous giant starspots, which are like sun spots but larger. The star propels a steady stream of ionised gases or plasma out in space. This wind is at least 50 times stronger than our Sun’s solar wind.

Unless there is a protective magnetic field, such winds have the potential to destroy any planet in habitable zone, writes The Hindu.

“The early Earth didn’t have as much protection as it does now, but it had enough,” said Jose-Dias Do Nascimento of the Harvard-Smithsonian Centre for Astrophysics (CfA) in the US and University of Rio Grande do Norte (UFRN) in Brazil.

Mars became inhabitable due to a lack of a magnetic field protection like that of Earth. Mars is barren and vulnerable to Sun’s intense solar winds. Mars’ atmosphere is almost negligible and is frequently stripped away by Sun’s high-energy particles.

“To be habitable, a planet needs warmth, water, and it needs to be sheltered from a young, violent Sun,” said Nascimento.

The study was published in The Astrophysical Journal Letters.

In another research, an international team of scientists have found the source of the alien cosmic rays that are bombarding Earth. It is being caused by a super-massive black hole, right at the centre of Earth’s Milky Way Galaxy. The team of researchers also include University of Adelaide researchers.

The high-energy cosmic rays that consist of charged atomic nuclei such as protons are accelerating towards Earth from the black hole. Its gravity so immense that nothing can escape its fierce grip, not even light.

The black hole has been given the name Sagittarius A* and now the scientists are confirmed that the cosmic rays are from this black hole and not remnants from dead stars, as previously thought.