Lunar Eclipse Tonight!

This year's only lunar eclipse happens tonight, and is visible throughout North America. It starts at 10:33 PST (that's 1:33 AM Tuesday for those on the East Coast), with total eclipse at 12:17 AM PST (3:17 AM EST) and ending at 2:01 AM PST (5:01 EST). Just a reminder - this is a lunar eclipse, which means that Earth will move directly between the moon and the sun; Earth's shadow will fall on the moon, darkening it and, during totality, giving the moon an eerie reddish hue.

Would you like to know more about eclipses? Say so in the comments section and I will be glad to devote a new post to the topic.

International Observe the Moon Night

Saturday August 18th is International Observe the Moon Night. With partnerships and sponsoring organizations all over the world, people everywhere will get the chance to observe the moon. For events near your area, click here. If you are in my area, come see me at Markham Park, where I'll be stationed with the South Florida Amateur Astronomers Association. We, like other groups around the world, will be showing people the moon through telescopes and talking about the moon, as well as offering hands-on activities for people of all ages. Hope to see you there!

For information about the event, visit the Observe the Moon website.

Will Mars Appear As Big As The Moon?

In a word, no. Let me say that again: NO.

Every summer since 2003, an email has been circulating which claims that on the night of August 27th Mars will appear as big as the full moon. Of course, even the email itself admits, albeit in tiny print, that this will only be the case if Mars is view at 75-power magnification.

The truth is that in 2003, Mars and Earth were closer in their orbits than they had been in a long time, or will be in something like 60,000 years. That said, the difference between Mars' appearance in 2003 and, say, 2005 was extremely negligible.

The good new? You can see Mars tonight in the night sky! In fact, if you time it right and the skies cooperate, you'll see Mercury, Saturn, Venus and Mars all once in the western sky at dusk. They'll all be gone by about 10 PM, so don't dally! (Oh, but also don't worry if it's overcast tonight; these planets will be all be visible together for the next week or so.)

Note: Even though you won't see the moon in those spots, since we're past those dates, you'll still the planets lined up like this through the end of the month. No telescope needed, so I don't want to hear any excuses!

On A More Personal Note...

I know I haven't posted in a while. I have good reasons, I promise. OK, one really good reason - our family's single "son" system went binary! I'm pleased to report that Little Dudestronomer is now a big brother to Baby Girlstronomer. I am going to try to keep things coming on the blog when I can, but things get more complicated in a binary system - ask any planet with more than one sun!

How Do The Phases Of the Moon Work?

(This is hands-down the best moon phase activity I've ever done. In fact, when I first did this - after 10+ years as an astronomy educator - my mind was completely blown. This is one of my top 3 favorite astronomy activities, so I hope you enjoy it.)

If you've ever tried to replicate the phases of the moon, you probably did it the way I used to, by going into a darkened room, turning on a lamp in the middle of the room and then standing around it with a styrofoam ball in your hand. I'm here to tell you there's a better way.
Go outside! Yes, it's that simple. Take your ball on a stick and use the real sun! You see, the phases of the moon are really varying views of the shadow side and the sunny side of the moon as seen from Earth. It's so much easier to do than to explain that I'm just going to tell you how to do the activity and trust that it will all become clear to you. If not, just shoot me an email and I'll be sure to answer any questions you may have.

Here's what to do:

1. If you happen to have a small white styrofoam ball on hand, great! Prop it up on a stick, skewer, pencil or whatever you can find. If you don't, look for something similar. Ping pong balls are white, but a little on the small side. Little Dudestronomer has a small glow-in-the-dark basketball that I use for this purpose, and I just hold it with my hand because he insists I not pop it.
2. Go outside on a sunny day. This activity is most effective if you do it while the moon is out and visible, so check your times and dates and aim for a date/time when you can see the moon during the day.
3. As you hold your ball up in front of you, you can face toward or away from the sun, but the best starting place is off to the side of the sun a bit. As you look at your ball, you'll see that part of it is illuminated by the sun, and part is in shadow. You did it - you demonstrated one phase of the moon!
4. To get the whole cycle, imagine that you're Earth and your ball is the moon. Since the moon orbits Earth, make your ball orbit you - that is to say, spin in a circle with your arm outstretched. As you do, you'll see the phase of your little moon change. In order to get it to look right, you may need to tilt your orbit a bit.
5. If you have the real moon out in the sky, see if you can get your moon to look like the real moon. If it's a first quarter moon, make your moon first quarter. How long does the real moon take to get from first quarter to full? 1 week. From full to third quarter? Another week. From third quarter to new moon? Yet another week. And from new moon back to first quarter? You guessed it, one week.

Here is an actual photograph from the first time I tried this activity with a group of educators through Astronomy From the Ground Up (though I'm not in the frame):

And to see if you're doing it right, your moon and the real moon should look like this (the real moon is to the right of the foam moon):

Kaguya Crashes

I'm a little behind the times on this one, but a couple of weeks ago, the Japanese spacecraft SELENE (nicknamed Kaguya) crashed into the lunar surface. This was a controlled collision that was complete after the orbiter successfully finished its 20-month mission studying the moon.
Kaguya orbited the moon elliptically, so that its oval-shaped path brought it closer and then farther from the lunar surface. Originally at a 100 km - 800 km orbital distance from the surface, it gradually got closer, first to a 50 km circular orbit, and then to a 20 km - 100 km elliptical orbit, eventually crashing into the moon.
The following is an image taken by Kaguya moments before it hit:

Make Your Own Craters

While we're on the subject of lunar impactors, I feel the need to share a fun crater activity with you. This one is very easy and easily adaptable to just about any age audience. The supplies you will need include:

- a large pan or tub (a pie tin could work, as well as a baking pan, but don't use anything breakable)
- flour
- Nestle Nesquik, instant hot chocolate powder, cocoa powder or any other brown powder you can find
- pebbles, marbles, other spheres of varying sizes and masses

First, you'll put a layer of flour at the bottom of your pan. Make it at least half an inch thick, up to an inch if possible. Smooth out your flour. Next, put a thin layer of chocolate powder over the flour so that none of the chocolate shows. Finally, make your craters!
This is the part that you can adapt very easily. You can choose to use the same size/mass object and drop it into the powder from varying heights (or throw it at varying speeds, but dropping from different heights achieves the same result with better accuracy); or you can see what different objects dropped from the same height do. Try throwing your pebbles onto the tray at an angle.
As the objects impact the powder, the flour will come out from under, simulating the way subsurface materials are brought to the surface during an impact event. In addition, the contrast of the white flour and brown powder make it easy to see the impact sites and details.
There are a million variations on this one out there, but the Night Sky Network has a good one available online as part of a suite of activities for LCROSS; you can get the PDF here.