The September Skies

The little planet Mercury will be very difficult to view this month. With binoculars, you may be able to detect it just above the western horizon after sunset.

Venus will appear low in the southwest evening twilight. More than 20 spacecraft have visited this planet, the brightest object in the sky except for the Sun and Moon.

Reddish Mars rises in the eastern predawn sky. It appears quite faint now because of its great distance from Earth.

Jupiter shines brightly in the eastern predawn sky. This giant planet is the fourth brightest object in the sky, after the Sun, Moon, and Venus.

Saturn glows in the southwestern evening sky, sinking lower each day during September.

The sun arrives at the Autumnal Equinox on Sept. 22 at 4:44 p.m. EDT. On that date, the hours of daylight and darkness are equal. This marks the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere.

OUR VIOLENT UNIVERSE

“Somewhere, something incredible is waiting to be known.”

– Carl Sagan,

1934-1996

Ancient astronomers believed the universe to be a place of relative calm, unchanging except for the wanderings of the planets among the peaceful, distant stars. Advances in technology have revealed a totally different picture and we now realize that the universe is actually filled with extremely violent events, many of which can have a profound effect upon life on Earth. We’re not talking about things that release lots of energy here on Earth, such as earthquakes, volcanos, hurricanes, tornados, etc. The violent cosmic events that we are concerned with in this article involve the release of much, much more energy than those relatively puny earthly phenomena.

Whenever and wherever these cataclysmic incidents occur in the universe, they are accompanied by enormous outbursts of high energy x-rays and gamma-ray photons, the most energetic known forms of light. This high-energy radiation can travel through space at the speed of light for billions of years, but when it reaches Earth’s atmosphere, it is blocked. This fact protects life on Earth from dangerous radiation but makes it very difficult to study the most violent processes that occur throughout the remote reaches of our universe.

However, in July 2012, the newest gamma-ray detector in the world began operations in Namibia at the H.E.S.S. Observatory, involving scientists from 32 different countries. They have already learned a lot about some of these unimaginably violent events that include the formation of supermassive black holes, the creation or merger of neutron stars, pulsars, x-ray bursters, and the destruction of massive stars in supernovae.

At least once a day throughout the year, a tremendous explosion in the remote reaches of outer space creates a brief but intense blast of very high energy gamma-ray radiation. These incredible flashes of gamma-rays usually last only a fraction of a second or perhaps a minute at the most.

While active, they outshine all other gamma-ray sources in the sky combined, then quickly disappear and never appear again in the same place. Gamma rays cannot penetrate through the atmosphere, so our eyes never evolved the ability to detect them. We only are aware of them because of the detectors onboard the orbiting satellites. Scientists believe that these gamma-ray bursts represent the most powerful releases of energy in the entire universe since the Big Bang, each burst equal to more energy than our sun will emit during its entire lifetime. Because these bursts come from hundreds of millions or even billions of light-years away and still outshine our Milky Way’s closest stars, our minds have trouble comprehending the stupendous amount of energy involved.

There are many other examples of violent processes taking place in our universe, some of which are have been vital to all forms of life. The heavy elements needed for life were all forged in the cataclysmic deaths of massive stars and these elements were flung far and wide by the explosions of novae and supernovae.

New stars are formed when huge regions of gas and dust undergo gravitational collapse, triggered many times from the blast waves created by these supernovae. The collision of galaxies also creates huge numbers of new stars as vast nebulous regions are compressed by shock waves. The atoms and molecules in our bodies and in all living things were formed in earlier generations of supernovae and the cycle keeps repeating as the evolution of the universe progresses. However, without extreme violence, neither life as we know it or the universe itself would exist.

Editor’s note: This monthly guide to the stars is from the Marshall Martz Memorial Astronomical Association and The Post -Journal. For further information, contact the M.M.M.A.A. at www.martzobservatory.org.