Bryan Shumaker NASA/JPL Solar System Ambassador
‘Look Up! What’s in the night sky?’
Another week has passed, fellow astronomers! We have been teased with a few mild days and a few days of sunshine, but we have a ways to go before Spring has really sprung.
I hope the weather has cooperated for the total lunar eclipse taking place the night of April 14-15.
Since I write this column a week in advance, I don’t know what the weather will hold, but I sure hope the eclipse is visible!
Full moon is April 15, so lunar observing gradually improves in the next week or so as a sharp line and good contrast appears between the lit and unlit areas of the moon.
Use binoculars or a telescope to enjoy the lunar landscape.
On April 25, 1990, the Hubble telescope was deployed.
It’s hard to believe that Hubble has been around over 23 years!
Probably no telescope in history is as well known or has enriched and educated so many people.
Hopefully, it will be around for at least another five to eight years, but with government funding always shaky, it may be touch and go.
Mars will soon be at opposition, which means it is brightest and most visible to us as it is opposite the Sun.
Look for a bright very ruddy star in the east and overhead by about 2 am.
Even with a telescope, the planet appears quite small, but you can clearly make out a round disk.
If you never seen Mars through a telescope before, try to find someone who has one and can show you just how it appears!
Last week I briefly discussed globular clusters in relation to the constellation Hercules.
These are spheres of stars, usually above and below the plane of the galaxy.
At least 160 are known to exist in our home galaxy, the Milky Way. At an average distance of 70,000 light years from us, they contain between 10,000 and a million stars, all packed densely into a few light years.
Imagine what a night sky must look like if you were on a planet in a globular cluster!
These stars are very old, far older than most of the stars in the galaxy.
How do we know this?
They contain very little metallic elements.
Metals are formed during a supernova explosion, when the titanic energies and heat cause simpler elements to fuse into heavy metals.
Stars which are destined to go supernova are large, burn their nuclear fuel fast and furious, and live a few hundred million years.
When they explode, they seed the cosmos with these metals and when newer stars form, these metals are incorporated into them—like our Sun.
The fact that almost all of the stars in globular clusters have almost no metal in them implies that they formed so early that they predated the supernova type stars—10 to 12 billion years ago (our sun is about 5 billion years old).
By the way, we can detect the presence or absence of elements in far off stars by carefully examining their spectra—the colored light we see when light passes through a prism.
It allows us to determine just what elements and simple molecules are present, even from a source billions of light years away!
I encourage you to give us a call or stop by at one of our monthly meetings of NOMAC (Northern Michigan Astronomy Club) held at the Raven Hill Discovery Center—only six miles south of Boyne City.
We would be delighted to show you the wonders of the heavens through a good telescope and explain just what you are looking at.
Telescope tune-up time is about here, and if you have a telescope and don’t know how to use it, it’s out of alignment, or there are mechanical problems with it—bring it to our meeting and we will help you get it back in great working order.
Check out www.nomac.net for more information.
Until next week, clear skies and keep looking up!