Tuesday, January 29, 2008

Astronomical Curiosities

I was checking out when sunrise and sunset will be occurring in Puerto Rico and found some cool information at timeanddate.com. If we get much sunny weather here in Michigan before I go, I want to be able to take note of the angle of the sun. According to the website, the sun is only at 33º above the horizon in Michigan this time of year. If you compare that with the summer solstice in June, the sun is 70º above the horizon, and is a marked difference as we all know. The primary difference we notice is a 15 hour day--how I love that time of year! But I also find that the quality of light is different. Winter light is more muted, don't you think? I attribute that to the fact that the sunlight travels through more atmosphere to get to us, due to the extreme angle of the tilt of the earth. Even though the sun is further away from us during the summer months, the atmospheric muck that it travels through to get to us is less dense due to the earth's tilt, giving us more intense sunlight. (I need to check my facts with my dad, who's studied such things, though I think I have it right).

I'm very curious to see what the light in Puerto Rico will be like. The day will be longer than here, at around 11 1/2 hours. The angle of the sun hits the island at 57º, which we hit on tax day, April 15, so it won't be quite so extreme as our summer, but I think it will be a notable difference in intensity compared to what we have in the midwest this time of year.

And since I'm close to the equator, I'll be seeing stars I've never seen before. I wonder if I'll be able to see the Southern Cross? I need to ask my dad about this.

I found a website with a star chart for what will be in the sky when I touch down in San Juan. I can see there are a few constellations that I'm not familiar with and that I've never seen before. That will be exciting, at least for me. Most notable are Canis Major and Canis Minor, the Big and Little Dogs. I see the Sculptor on here as well, though I've never heard of him. If I get up at 3:00 in the morning and stroll along the beach, I'd see part of Hydra and Crux--though I don't think that's THE Southern Cross. I'd also be able to see Virgo coming into view, which I've never seen before. I think on a clear night, insomnia wouldn't be so bad.

Seeing Virgo makes me realize that I'd also be able to see a few other constellations of the zodiac, Cancer, Leo, Pisces and Taurus, which I don't think I've ever seen before either.

If I looked northwest at 3:00 a.m., I'd see Andromeda, home of our nearest galactic neighbor, and just next door would be Cassiopeia, and if I look up, perhaps most exciting of all for me would be able to glimpse Cygnus the Swan.

I'm going to make sure to carve out some quality star gazing while I'm down there.

I don't think I want to sleep much--there are too many things to do!


alison said...

Since we live in a north facing house, surrounded by wooded hills I really notice light. Ironically, our house gets more light in winter, because the sun is lower in the sky. It's just high enough to get over the back hill, but not so high that it shines only on the house. Our wide eaves shade us from so much light, but the winter sun is at just the right degree that it hits under them.

I am so happy that you are going to PR, and fantastically envious that I am not.

Dan said...

I wish everybody was going.

I'll be sure to soak up lots of rays for you Alison.