What's Up This May

Shortly after sunset, you may notice fewer stars are visible than just a few months ago. The Earth has moved along its orbit around the Sun causing the night side of Earth to face different stars than we saw at this time in December. Mighty Orion the hunter is lost in the Sun’s glare while the more sedate stars of spring come to dominate the evening sky.

Venus continues to blaze brightly in the western sky after sunset, but it will be lost in the glow of twilight by the end of the month. The slender crescent Moon will pass by Venus on the evening of May 22.

Red planet Mars appears high in the south after sunset, hanging just below Leo the lion. Mars is dim and unimpressive now and sets with little fanfare after midnight.

Meanwhile, Saturn is still in the constellation Virgo the maiden just above its only bright star, Spica. Compare the color and brightness of these two.

May is a great month to look for the Big Dipper because it is as high it gets in the northern sky. Look for it just above the back of Leo. Check the front of this month’s chart to see how the Big Dipper can lead you to the Little Dipper and the North Star, also known as Polaris.

The Summer Triangle is just beginning to creep above the eastern horizon at 9 pm. The first of these three stars to rise is Vega, in Lyra the harp. See the June 2009 chart on our web site for more information about the Triangle and other summer constellations. (Remember that the planets move through the constellations over time, so ignore planet information on that two-year-old chart!)

What is Natural Selection?

On Thursday, May 17, starting at 7 pm at Adventure Science Center, Dr. John Niedzwiecki of Belmont University will ask visitors the question “What Is So Natural About Natural Selection?” during Adventure Science Center’s monthly Science Café.

Get Ready for the Transit of Venus

On June 5, 2012, many people will be completely unaware that an extremely rare event is taking place in the sky: Venus crossing directly in front of the Sun.

Venus regularly passes between the Earth and Sun, but because our planets’ orbits are tilted, most of the time Venus passes slightly above or below the solar disk. But on June 5, Venus will pass directly between the Earth and Sun in an event called a Transit of Venus. From Earth, it will appear as a tiny black dot slowly moving across the face of the Sun. The last time this happened was in 2004, and after June it will not happen again until the year 2117.

Edmund Halley, best known the comet that bears his name, realized if two observers, thousands of miles apart on the Earth, carefully measured the time it takes for Venus to cross the disk of the Sun, they could use trigonometry to calculate the distance to the Sun. From this, astronomers could then determine the actual size and scale of the entire solar system.

Today we very accurately know the distance from the Earth to the Sun and to other objects in space. Meanwhile, earthbound telescopes and spacecraft are searching for planets orbiting distant stars. A planet transiting in front of its parent star dims that star’s light by a very tiny bit. Careful measurement of that starlight allows astronomers to "see" that planet. The Kepler spacecraft has already discovered hundreds of planets orbiting distant stars.

This will be only the seventh Transit of Venus deliberately observed by humans. One person watched in 1639. For the transits of 1761 and 1769, observers fanned out around the globe to time the event. On June 5th, 2012, you can join millions around the world to watch this rare alignment of the Sun, Earth, and Venus.

To get ready for the Transit, visit us at SudekumPlanetarium.com/tov/. You’ll find detailed information about how to safely observe the Sun, the people and history behind the event, and how timing a transit was crucial for the advancement of science in the 1700s.

Astronomy Day: Transit Time

Astronomy Day will be June 2 at Adventure Science Center from 10:00 to 3:30 pm. Discover how to safely observe the Sun and enjoy daytime astronomy. Prepare for the Transit of Venus, which will occur on the afternoon of June 5. See sunspots (weather permitting) and participate in other astronomical activities.

Transit Tales: Venus and the Epic Search for the Size of the Solar System

Wednesday, May 16 at 7:30 pm
Monthly Meeting of the Barnard-Seyfert Astronomical Society
Cumberland Valley Girl Scout Council Building
4522 Granny White Pike, Nashville

Only two people saw the Transit of Venus in 1639. In 2012, millions will pause to observe this rare event, either in person or on the internet.

June 5-6 2012 marks only the seventh time in recorded history when human beings will have looked toward our Sun to deliberately witness the planet Venus crossing the solar disk. Observing this rare astronomical alignment allowed astronomers to calculate the distance from the Earth to the Sun. For the first time, we had an idea of just how big space really is.

BSAS member Theo Wellington will delve into the scientific importance, history, and modern benefit of observing transits. Learn how you can safely observe, photograph, and contribute observations of this Transit of Venus. Will you be watching?

Skip This Eclipse

On May 20, there will be an annular solar eclipse, best viewed from China and Japan. None of it is visible from Middle Tennessee*. The Moon will make first contact with the solar disk just as the Sun disappears below our western horizon.

Even if you did travel to Asia, it’s only an annular eclipse, meaning that on that date the Moon is too far away to completely cover up the Sun. The Sun will appear as an annulus, or ring, around the silhouette of the Moon. People in the western U.S. will get to see some of the partial phase, and locations along a narrow path leading from northen California to northern Arizona will see the annulus.

You’re best off just waiting until August 21, 2017, when a total solar eclipse is visible from Nashville! Consider this year's Transit of Venus good practice for learning safe solar observing techniques.

*Technically, the Sun is partially eclipsed in Nashville too, but it begins so close to sunset it will be virtually impossible to see.