Happy Fall - if you're living in the Northern Hemisphere.  Otherwise - Happy Spring for my Southern Hemisphere friends. 

What do we wish to our fellow humans orbiting the Earth in the International Space Station? 

Anyway, today marks the September Equinox, the start of Fall in New England, at least.  The word "Equinox" means "equal night."  That is, theoretically, we'll have a day with 12 hours of sunshine and 12 hours of night.  Equal. 

In practice, things aren't so equal.  Because the Earth has an atmosphere (I'm not complaining), the Sun will (by refraction) actually continue to appear above the horizon even when it has dipped just below.  And the Sun's light gives us dawn and dusk even at those below the horizon times.  Not exactly equal. 

Why is the Equinox happening today at 10:21 A.M., then? 

The Earth spins on its axis, but that spin axis is tilted by about 23½º.  During the (Northern Hemisphere's) Summer Solstice, the North Pole is angled most towards the Sun, which is overhead at a latitude of 23½ºN.  About three months after the Summer Solstice the Sun crosses the "Celestial Equator," which is the Earth's Equator projected into space.  At this moment we turn to Fall. 

Because of leap years, the Equinox is not always on September 22. 

All this orbital dynamics is often more easily explained using a planetarium.  If you're interested in learning more about Blue Star Planetarium, check out the website here, or email your questions any time.

Marc

I'm a Summer kind of guy.  I love Summer.  I spent over a year in south Florida in one stretch and it was great.  It was the longest Summer I had, until years later when I worked at a college planetarium in the United Arab Emirates.  That was Summer to the max.  We stayed there three and a half years, apart from travel back to the U.S. during Summer recesses.  It was always Summer, and it was good. 

I don't know why, but this year I've pretty much had it with the Summer.  Maybe it was the mix of hot days and almost no rain for weeks, though that was certainly the case in Dubai.  I guess I'm just getting older - bring on the Fall!

I introduce the blog this week in this way to contrast this Summer to what happened 200 years ago - 1816, the "year without a Summer."  Read more about it here.  

To summarize - during the Summer of 1816 there were severe frosts every month.  Crops were drastically reduced, leading to famine across the U.S., Europe, and China.  New England was particularly hit hard.

What caused the "year without a Summer?"  It has been attributed to the ash in the atmosphere from the 1815 volcanic eruption of Mount Tambora (now in Indonesia).  This was the largest volcanic eruption in at least 1300 years, and lowered the global average temperature by about 1ºC.  That small temperature change can and will make a big difference. 

So I will try to not complain about the Summer this year, but I'm still looking forward to Autumn... :)

Marc R.
www.bluestarplanetarium.com

Did you hear the news?  Astronomers have discovered over 3000 planets now around other stars in our galaxy, but they've just announced that they've discovered a planet around the closest star to our own Solar System, Proxima Centauri. 

Even though it is the "closest" star, it's still around 25 trillion miles from us, or about 5000 times further away than Neptune, the furthest planet of our Solar System, is to the Earth.  Light, which travels at 186,000 miles per second, takes over four years to span the distance. 

The new planet, dubbed Proxima Centauri B, is estimated to be at least 1.3 times Earth's mass, and orbits its star every 11.2 Earth days.  But because the star's luminosity is so low, the planet is predicted to be in the zone where temperatures would allow for liquid water on its surface. 

Water has not been discovered on the surface at this time, and there is no evidence at this time of life on the planet.  But it does go to show that even when you put your gaze out across the Universe, you never know what you'll discover just next door. 

For more information about Blue Star Planetarium, visit www.bluestarplanetarium.com

Marc

What will you be doing 365 days from now?  Hopefully you'll be under a cloudless sky watching a solar eclipse.

A solar eclipse, as a reminder, is what happens when the Moon crosses in front of the Sun.  The Sun can be partially or totally covered.  This only happens when the Moon is in its "New" phase.  We don't have solar eclipses every New Moon because the Moon's orbit is tilted relative to the Earth's - some months the Moon is "above" the Sun, some months "below."  Twice a year everything lines up for the eclipse. 

Unlike a lunar eclipse, which is visible for over half the planet, a solar eclipse is visible over a smaller portion of the surface, and for a total eclipse the path is quite narrow - about 100 miles wide. 

So total solar eclipses are a big deal - people travel around the world to see them.  There hasn't been a total solar eclipse anywhere in the continental U.S. since 1979.  That drought ends next August 21.  As if to make up for the recent lack of eclipses - we get a second one in April of 2024!

The 2017 total solar eclipse path enters the U.S. in Oregon, goes through Idaho, Wyoming, Nebraska, Kansas, Missouri, a small piece of Iowa, Illinois, Kentucky, Tennessee, Georgia, and exits into the ocean off of South Carolina.  See the eclipse path here:

If you're not on the path of totality, the rest of the "Lower 48" will get a partial eclipse.  Most of New England will have at least a 60% eclipse.  Of course that's still not enough for direct viewing of the Sun.  In upcoming posts I'll give more information about the eclipse and how to observe it safely. 

This year, the Blue Star Planetarium will deliver programs to school and other youth groups and will be discussing next Summer's eclipse.  For more information about the traveling planetarium, visit: www.bluestarplanetarium.com

Any questions about the planetarium or the eclipse - email bluestarplanetarium@gmail.com

Marc Rouleau,
owner/educator

Welcome to the new blog for the Blue Star Planetarium.  Blue Star Planetarium offers traveling planetarium programs to schools and other groups across Massachusetts and neighboring states. 

In today's edition - an invitation to watch a great celestial show, the Perseid Meteor Shower. 

Meteors, or shooting stars, are pieces of dust or ice which orbit the Sun and enter the Earth's atmosphere.  The extreme friction between these particles and the air causes the bits to burn up and light up the sky. 

This particular meteor shower peaks on the evening of August 11/12.  Best time to view is after midnight and after the Moon has set, but earlier watchers should still see something.  Your best bet is to let your gaze take in as much of the sky as possible. 

This month's shower is named for the constellation Perseus.  It is from this constellation that the meteors appear to originate. 

Enjoy the warm Summer nights and the Perseid Meteor Shower!

Marc Rouleau
Owner, Educator
Blue Star Planetarium