Stargazing is a wonderful and peaceful past time that anyone can enjoy. From planets to star clusters, galaxies to nebulae, the night sky is a treasure trove of heavenly delights. Although astronomy and stargazing are traditionally done in the dark field, our glorious moon can also be appreciated from the city.
The moon was created about 50,000 years after Earth formed 4.5 billion years ago. After the sun was set, fine particles of dust began to come together, creating larger pieces of sand. The "snowball" effect continued as more things gathered and accumulated in rock, gravel, and small size asteroids.
Over the next hundred million years, this process has formed about 100 baby planets called planetesimals. Like a cosmic demolition derby, they orbited the sun at different speeds and directions. One of these bodies, called Theia, measuring the size of Mars or half of Earth's body, hit our world with a glance, causing it to tilt and ejecting molten rock into space. Like Saturn's rings, the fused debris formed a ring around our planet and began to unite with what we see today. At that time, the moon was only twenty thousand kilometers away, compared to its average orbit of 386 thousand kilometers. The moon is still moving away from us the width of a golf ball a year.
When the melted moon was slowly cooling, lighter materials rose to create a thin semi-smooth crust. The last heavy bombardment (LHB), which lasted tens of millions of years, flooded the Earth and the Moon, as did other planets with asteroids and comets. The primitive earth looked like the moon today. Some massive asteroids fractured the thin lunar surface and allowed molten lava to float and flood certain areas. These are the lunar seas that appear as the softer and darker regions.
The close distance of our two worlds creates a "tidal lock" that allows us to see approximately one side of the lunar surface. The so-called "dark side of the moon" is simply the opposite side that the Earth does not see except for the Apollo and other missions that mapped this side in great detail. Except for about five days of the moon's 29.5-day orbit, we see our natural satellite in several phases.
Through the eyepiece of a telescope, you can observe craters measuring only a few kilometers in diameter. From night to night, long, short shadows produced by the sun, provide a slightly different face. The "terminator" is the dividing line between lit and erased areas, it produces dramatic shadows. When doing terrestrial photography, the full moon will accentuate your portrait of mountains or distant trees during dusk, but it is the worst time to see with a telescope. Craters appear as circles without depth.
And on the subject of photography, the moon is bright enough to be photographed through a telescope. Unlike long exposures of constellations and other weaker objects, where a telescope motor drive is needed to secure point stars, the bright moon requires extremely short exposures. There are now adapters that allow you to connect your smartphone to the telescope eyepiece.
Sightings of the International Space Station
Until next time, clear skies.
Known as "The Backyard Astronomer," Gary Boyle is an astronomy educator, guest speaker and monthly columnist for the Royal Astronomical Society of Canada. He was interviewed on over 50 Canadian radio stations and on local TV in Ottawa. In recognition of his public reach in astronomy, the International Astronomical Union honored him with the name of Asteroid (22406) Garyboyle. Follow him on Twitter: @astroeducator or his website: www.wondersofastronomy.com
Latest posts of Gary Boyle (see it all)