POSTED 26.07.2018
STAR PROVES EINSTEIN RIGHT
It may seem scary to be encircling a massive Black Hole which is 4 million times the mass of our Sun but that’s what the Earth and all the stars of our Milky Way Galaxy are doing all the time.
When you consider that our Sun itself is big enough to swallow more than a million Earths then the size of the Black Hole named Sagittarius A* is difficult to imagine.
The first discovery of a cluster of stars in our Milky Way was made in 1601 by the astronomer Galileo Galilei using a hand made telescope. Now over 400 years later giant telescopes have detected some 100 billion more stars in our Galaxy alone.
The discovery of the Black Hole took astronomers at the giant ESO Observatory (European Southern Observatory) in Chile 16 years to confirm in 2008.
Even more challenging was the recent discovery of a star which came so close to the Black Hole that its effects could be measured by scientists on Earth 26,000 light years away.
It took the combined data from giant telescopes in Chile and Hawaii together with that gathered by the Hubble Telescope which orbits the earth every 97 minutes before scientists could confirm the data.
The intense gravity of the Black Hole had caused the star later named S2 to lose energy.
The scientists from the Max Planck Institute for Extaterrestrial Physics (MPE) who examined the data called this “gravitational redshift”.
What was even more interesting to our understanding of the Universe was that this process had proven that Einstein theory that gravity is bent spacetime was right.
In 1916 Einstein found that the mass of an object or galaxy curves spacetime.
It was also the universal force that kept planets and stars in their orbits.
In this case the gravitational field of the Black Hole showed how the wavelength of light from the star had changed as its light became stretched.
While the black hole itself, a defunct star, will eventually burn itself out as gravity forces its collapse, it will also be gravity that keeps the Earth in its orbit so that it avoids the same fate because as we now know gravity behaves the same way in distant galaxies as it does on Earth.
Science Magazine June 2018
Astronomy and Astrophysics July 26 2018
www.science.org.au -understanding gravity warps and ripples in space
Copyright Mica Jay