What’s Up in the Sky – September, 2016
Earth’s Cousin May Be Very Close By
Algebra doesn’t change much. The Algebra I taught at St. Augustine Seminary HS in 1970 was pretty much the same as the Algebra I taught at Fennville HS in 2002. Astronomy, on the other hand, does change . . . drastically and profoundly. Sure, solving the Four Color Theorem (a famous problem in mathematics that was proved in 1976) was an example of change, but it didn’t alter the basic framework of mathematics. On the other hand, recently astronomers have made discoveries that drastically changed how we view the universe.
For example, we have known that the universe is expanding since Edwin Hubble’s observations in the 1920’s. This immediately brought up the fate of the universe – would it keep expanding forever, reach equilibrium, or collapse back on itself? Then in 1998 we discovered that the expansion was actually accelerating and, in an attempt to explain the observations, astronomers have been searching for dark matter and dark energy ever since. Now, that’s a BIG change.
Then there are exoplanets, planets that orbit stars other than the Sun. In 1984 a disc of material was shown to exist around the star Beta Pictoris, confirming current theories of planetary formation. Then, in October of 1995, the discovery was made of the first planet (a Jupiter – sized object with a very short “year”) in orbit around another star.
We now know of 3,374 exoplanets and estimate there to be on average two for every star in the Milky Way. That doesn’t mean all stars have planets, some may have eight or ten and many may have zero. But the latest discovery sheds some light on the question: how common are planets?
Last Wednesday, a group of thirty-one astronomers in the UK announced the discovery of a planet orbiting the star Proxima Centauri, which my former Astronomy students will tell you is the star closest to us in the galaxy. In addition to its close proximity to us (which explains the name of the parent star), what is even more astonishing is that this planet might be quite similar to our own planet, Earth.
The Keppler Space Telescope has shown that most of our galaxy’s planets are terrestrial, that is, Earth-like, small and rocky rather than gas giants like Jupiter. The newly detected planet is at least 1.3 times the mass of Earth and lies in the “goldilocks zone”, where its temperature allows the presence of liquid water on its surface.
However, we don’t know the composition of the planet nor its habitability. New instruments under construction should be able to image the object directly, giving us insights into these questions.
No matter the final analysis, it is a very exciting discovery, one that should allow us an even better understanding of what’s up in the sky.
This month in history:
∙ Sept. 3: Last two Apollo Moon landings canceled by NASA – 1970
∙ Sept. 8: Voyager 1 launched – 1977
∙ Sept. 18: Photo of Earth and Moon together in space taken by Voyager 1 – 1977
∙ Sept. 20: Wernher von Braun arrives in US – 1945
∙ Sept. 23: Premier of “The Jetsons” – 1962
∙ Sept. 30: End of daily communication with Pioneer 11 – 1995