Of Earth-like planets and black holes

Plenty of  mind-blowing astronomy news the last few days, probably because of the ongoing NASA conference in California where they are presenting a lot of  exciting material on recent discoveries.

...However, those two planets are "orbiting stars smaller and cooler than our Sun," NASA said in a statement, noting that Kepler-22b "is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our Sun."....

....A total of 48 exoplanets and exomoons are potential habitable candidates, among a total of 2,326 possibilities that Kepler has identified so far.....

Two monsters, one of which may be about 20 billion times the mass of our sun, could provide important clues to the formation of galaxies.....

....Astronomers are fairly certain that every galaxy — including our own — has a supermassive black hole at its center. These black holes' existence was proposed four decades ago to account for the high-energy bursts of radiation, known as quasars, from distant and ancient galaxies.....

And, this from an event that was observed on Earth early this year.

.....Ashley Zauderer, an astronomer at the Harvard-Smithsonian Center for Astrophysics who led the second study, which focused on the radio wave emissions, recalled thinking, "This is crazy."

"I didn't believe it," she said. "I called a colleague and said, 'Will you make sure I didn't make a mistake? Look at this data, it's too bright.'"

Zauderer's radio-wave study mapped the location of the burst to the centre of the galaxy, right where a black hole ought to be.

The researchers concluded that the strength and recurrence of what they were seeing could best be explained by a supermassive black hole ripping a star apart and shooting out a jet of radiation in the process.

How did it happen? The team's theory is that a star about the same size as our Sun ended up too close to the black hole. The black hole exerts a powerful gravitational pull - it contains the mass of about a million Suns - and that caused the side of the star nearest the black hole to stretch toward it, in much the same way that the moon causes the tides on Earth.....

...The likelihood of seeing another star get swallowed up is slim, Burrows said, but that won't keep the team from looking - especially now that they have an idea of what to look for.

"It might happen once every 10,000 years in a galaxy with a supermassive black hole in the centre," Burrows said. "But there are a lot of galaxies out there in the sky."