We're just around this week. (Dennis Mammana photo / creators.com)
This week, like every month, the moon shines beautifully in our evening sky.
We astronomers know the patterns of the moon very well, and we often plan our observing programs around its dimming light. Whenever I'm invited to an event and I have to decline because of the moon phase, the looks I get are priceless.
As the spring weather increases, it might be fun to look at the moon with interesting new insights about our next cosmic neighbor. That's how it works.
Our moon is an average of 238,855 miles from Earth, but its distance changes during the month. This is because the moon orbits our planet not on a circular path, but on an ellipse. When it is closest (perigee), it can be about 225,623 miles away and farthest (apogee) about 252,088.
How long would it take to cover this distance? Of course, that depends on the speed with which we travel. For example, if we were driving at an average speed of 60 miles an hour ̵
Suppose we could stand on the moon. Since the Moon is much less massive than the world we live on, its attraction is also much lower – one-sixth of what we normally feel. This means that a person weighing 120 pounds on the earth weighs only 20 pounds on the moon.
The weaker lunar gravity would affect most of what we got used to. For example, imagine watching a moon ball game with a towering ball sailing home before it finally lands!
Also on our natural satellite, temperatures are different than on Earth. Because the moon has no significant atmosphere to absorb the sun's heat and distribute it around the moon, temperature extremes are common. A thermometer in direct sunlight would register about 273 degrees Fahrenheit, while one in the dark would show a blowing minus 244 degrees F.
The visible features of the moon are also quite interesting. The great dark regions are ancient layers of solidified magma known as Mary, and they always seem to meet us here on Earth. Does that mean the moon is not rotating?
Not at all. The moon is spinning, but the earth's relatively strong gravity has trapped a face in our direction. It's like tying a rope to a bucket handle and swinging the bucket around you. The open part of the bucket is always up to you, although other people would see all parts of the bucket while sailing around you.
If the weather is nice this week, I hope you go outside to do some moongazing. It's always fun to think about some of these amazing facts as I spend time with our next heavenly neighbor.
– Dennis Mammana is an astronomy writer, author, lecturer and photographer who works under the clear, dark Anza sky. Borrego desert in the San Diego County backcountry. Contact him at [email protected] and follow him on Twitter: @dennismammana . Click here to read the previous columns. The opinions expressed are his own.