What’s Up in the Sky – June, 2020
Spaceships, Galaxies, and Planets, Oh My
A newspaper column with a name like What’s Up in the Sky probably should be about things that are visible when you go outside and look up. Of course, loyal followers of the column know that its topics often include famous people, places, and events related to the science and history of astronomy. These topics usually appear when the sky offers less than memorable views or when the fun stuff can only be seen an hour or two before sunrise. So today I offer a potpourri of unrelated topics in an attempt to expand my readership.
I am old enough to remember the days of Sputnik, John Glen, and Apollo 13. After the last two Moon landings were cancelled we saw leftover Saturn rocket parts become SkyLab and watched astronauts cavort around the spacious accommodations sucking up floating liquids and playing with gyroscopes.
Then NASA embarked on a mission to take women and men into space on a regular basis in a reusable spacecraft to do important work – like putting the Hubble Space Telescope into orbit. But the Space Shuttle didn’t work out as we had hoped. It was massively complicated, difficult to service and extremely expensive. The Challenger and Columbia disasters more or less sealed its fate. The last shuttle launch was July 8, 2011, and since then all our astronauts have traveled to the International Space Station (ISS) on Soyuz rockets launched from Russia.
That’s about to change and if yesterday’s launch of the SpaceX Crew Dragon was successful, it already has. We are now in the era of private ownership of satellites, launch vehicles, and manned spacecraft. Soon we will have space tourism and commercial space travel a la 2001: A Space Odyssey.
Launched on Falcon 9 rocket, NASA astronauts Robert Behnken and Douglas Hurly will reach the ISS 24 hours later when the Crew Dragon docks itself. They will join the three astronauts currently on board.
Although the mission was first planned to last only two weeks, NASA released a statement that “the specific mission duration will be determined once on station based on the readiness of the next commercial crew launch.” This historic event marks not only the first humans launched into space on a privately owned spacecraft but also the first manned rocket to be launched from U.S. soil in nine years.
Next, I recently received an inquiry from a friend regarding the colors of galaxies as seen in photos from The Hubble Space Telescope. The HST uses CCDs to record incoming photons of light and it is sensitive not only to visible light, but also infrared and ultraviolet light which are invisible to the human eye. A star’s color depends on several factors, temperature, age, mass, size, but mostly temperature. So astronomers learn a great deal about the star’s temperature and chemical composition by analyzing the colors of the light it emits.
Galaxies are made up mostly of stars but there are also plenty of elements in gaseous form between the stars. Astronomers will often record images through various filters to study specific properties of the galaxy, such as the abundance of hydrogen or other elements. They then digitally enhance the photos to represent the different colors. These are usually accurate conversions where infrared would be represented by red, ultraviolet by blue, for example. Also, due to the expansion of the universe, extremely distant galaxies’ colors will be shifted toward the longer, red wavelengths.
A galaxy’s color will also depend on the age and mass distribution of its stars. Young, hot, massive stars emit mostly blue light while old, cool, giant stars are reddish. Betelgeuse and Rigel in Orion are examples.
Finally, June will offer several somewhat challenging opportunities for observing, beginning with the planet Mercury. Always a challenge, you will have to have a clear horizon and probably a pair of binoculars. Start by finding the stars Castor and Pollux in the western sky. Work your way down to about one fist-width above the horizon and you should be able to spot it. It won’t be very bright, but it will be pretty much alone.
Even more challenging will be a very close encounter between Venus and the crescent Moon on the morning of June 19. Starting around 5:30 a.m., scan the northeastern horizon below the Pleiades with binoculars or a telescope. With luck (and perfect weather) you will see the thinnest of crescents next to Venus. Then turn around to see Jupiter and Saturn in the southwest. I mention those two planets because next December they will put on a fantastic show up in the sky.
This month in history:
June 02: Surveyor 1 lands on the Moon – 1965
June 05: Regular observations of Neptune begun by Voyager 2 – 1989
June 10: Mars rover “Spirit” launched – 2003
June 16: Valentina Tereshkova first (and only solo) woman in space – 1963
June 18: Sally Ride becomes first American woman in space – 1983
June 22: Evidence of liquid water on Mars announced by NASA – 2000
June 30: Tunguska impact flattens hundreds of miles of Siberian forrest – 1908
