What’s Up in the Sky – December, 2017
2017 – An Historic Year for Astronomy
What must it be like to devote an entire career to the study of a particular field and in a period of about two months have two discoveries made for the first time in history? That’s what has happened to astronomers recently.
The events that have the astronomical community in orbit are the detection of two colliding neutron stars and the discovery of a fast-moving object from outside our solar system passing the Sun.
About 130 million years ago in a galaxy far, far away, two neutron stars – the strange, compacted cores of dead stars – crashed into each other. Known as a “kilonova” the explosion sent ripples through space-time and ejected heavy elements such as gold and platinum into space. That’s one new discovery right there – it was previously thought that these elements were formed in the supernova explosions of massive stars.
Several things make this observation so astounding. One is its rarity – astronomers estimate that such a collision occurs in a galaxy like our own perhaps a few dozen times per millions of years. Another is the fact that not only were the gravitational waves from the resulting explosion detected by LIGO, but also, two seconds later, scientists detected a flood of electromagnetic radiation from across the spectrum. This has allowed astronomers and astrophysicists to verify theories concerning some of the most fundamental questions in physics.
In addition verifying the source of heavy elements, they were able to show that gravity waves travel at the speed of light, determine the source of gamma ray bursts, and measure the expansion of the universe much more accurately. Not bad for a single observation.
The second historical event is notable more for its rarity rather than any revealing data it provides. But it is still pretty cool. I’m referring to the discovery of the first observed object known to have originated from beyond our solar system. That determination was made based on its speed and trajectory. It is currently speeding out of our solar system into interstellar space.
Actually, this is not the first interstellar object to make its way into our solar system. Spacecraft have collected and returned samples of interstellar dust and grains of it can be found in meteorites. But this was the first “macro object” of extra-solar origin to be observed.
Regarding the importance of this discovery, Paul Chodas with the Center for Near-Earth Objects Studies said, “we have been waiting for this day for decades”. It was another confirmation of the long-held theory that objects moving between the stars occasionally pass through our solar system.
All in all, it’s been a good year for what’s up in the sky.
This month in history:
Dec. 7: Galileo spacecraft enters Jupiter’s atmosphere – 1995
Dec. 8: Dragon 1, first private spacecraft to be recovered from orbit, is launched – 2010
Dec. 14: Gene Cernan, Apollo 17 astronaut, is last human to walk on Moon – 1972
Dec. 14: Tycho Brahe born – 1546
Dec. 20: Founding of Mt. Wilson Solar Observatory – 1904
Dec. 24: Apollo 8 astronauts give us inspirational moment from lunar orbit – 1968
Dec. 25: Isaac Newton born – 1642
