It’s official: it’s autumn in the Northern Hemisphere (which is where Astropotamus lives). And as everyone knows, on the equinox, there are equal parts day and night, right? Oh, and that you can balance an egg on its end, too. Surely this is all true?
We take a break from astroimaging for a moment to talk about things that go bang. We all know about fireworks, smash-em-up derbies, and an obscure rock group from the early 70s. But I’m talking about things that go bang in the sky.
Today, we’re going to pretend we are a photon of light, rather than looking at photons of light. This lets us take a break from time traveling for a minute and spend some time talking about what happens to light when it goes through the Time Machine and ends up on the sensor of our camera. Continue reading »
Traveling back in time billions of years is fun, but sometimes it’s also fun to be in the present. Especially when it involves Mrs. Astropotamus. Continue reading »
Astropotamus has been absent this summer from the Time Machine. This is due, in part, to being busy, but also because it’s somewhat frustrating to take image of the heavens with the camera that I put at the end of the Time Machine. Luckily, I just bought a new one.
Do you know how big one square centimeter is? Point your index finger at your eye. The end you see is about a square centimeter. Do you know how big 65,000,000,000 is? It’s 6.5E10 in scientific notation. It looks big. Considering that there are about 1E19 atoms of air in a cubic centimeter of air at sea level, 65,000,000,000 starts to look small. But what if I said that every second, about 65 billion solar neutrinos pass through every square centimeter of the Earth that is aimed at the sun? Seems like a pretty big number now, doesn’t it?
Time Machines do their best work at night. If you’ve ever slept in a tent, you know that dew does, too. Which is why dew is the enemy of every Astropotamus. We use all sorts of things to get rid of it when it shows up. Mostly hair dryers and big tubes on the end of our Time Machines. Sometimes we use electric heaters like you have on your car’s rear window. In the end, it’s all about physics.
If Astropotamus looks at the moon with his eyes, it looks beautiful. Just like is has for billions of years. Bright, crisp, full of dark splotches and light splatters. If I use my Time Machine and look at what the moon looked like 8 minutes and 14 seconds ago, I’m sometimes disappointed. I can’t see the moon as clearly through the eyepiece of the Time Machine as I can with my naked eye. Very frustrating! What’s up with that?
Does the moon spin? Yes. It rotates once on its axis approximately every 29.5 days. This is why we always see the same face of it, because it rotates once about the Earth’s axis in the same period. Does the moon rotate? Well, if you look down (or up) at one of the polar axes, it will rotate about the axis – this is the same as “spin” so, I suppose yes, the moon rotates. Does the moon flip? Reverse? Mirror image? Transmogrify?
I think this is getting complicated…
Do you know when Easter is? It’s the first Sunday after the first full moon after the spring equinox. That can be a complex calculation to make. In 2011, the full moon in March was the 19th. About 36 hours before the spring equinox. 29.5 days later will be the next full moon – April 18th. It happens to be a Monday, which means that Easter is six days later on April 24th, 2011. I wonder what the latest possible Easter Sunday is?