Yo! Did you know that Jupiter’s moon Io is the most volcanically active world in the solar system?
Io is the size of our Moon but a very inhospitable place. It’s covered in sulfur which makes pretty shades of yellow but unbreathable air.
To make matters worse, Io is so small and Jupiter is so large that Jupiter’s gravity causes 100 meter land-tides on Io’s surface. Yes, the land rises and falls 330 feet as Io orbits Jupiter. No wonder Io has more than 400 active volcanoes!
In 2007 NASA’s New Horizons spacecraft took photos of a plume coming off the top of Io. What was it? A volcanic eruption rising 300 miles above Io’s surface!
Click on the screenshot above (or click here) to see a video of Io in action.
Even after the coldest winter the east-central U.S. can remember, the average U.S. temperature was 0.5 degrees above normal. (Ask Westerners how hot they were!) Here’s a month-to-month video that shows that even the East was hot in December.
Climate scientists agree(*) that the warming is caused by humans and there will be sobering results. We’ve caused it. We record it. We report on it. But will the news change anything?
On a political and media level in the U.S. this news has generated interest and talk but no real action. On the natural level — among the air, water, birds, plants, and animals that I care about — it is big news and they’re doing something about it. The air is hotter, the ice is melting, the sea is rising, and the plants, animals and birds are moving north or uphill.
Humans are doing something too, even here in the U.S. where our society has not taken up the cause.
When the sky is clear on cold January nights, the planet Jupiter shines brighter than the stars. Step outside with binoculars and you can see up to four of its moons.
These are the Galilean moons, named for Galileo because he was the first to report them in 1610. He used an improved 20-power telescope that wasn’t even as good as today’s birding scopes. When the moons are in the right position you can see what Galileo saw — something like this.
However on the night of Friday January 23 you’ll need a real telescope to view them because three of the moons — Europa, Callisto and Io — will transit (pass across) the disk of Jupiter and cause eclipses on the planet.
Above, the Hubble Space Telescope captured Io playing “Me and My Shadow.” At one point on January 23-24 all three moons will play this tune.
Astronomy.com calls it a triple shadow transit. Click here for their drawing of what you’ll see in the telescope at 1:40am EST on January 24.
This is your last chance to witness Jupiter’s triple shadow transit until 2032, but it’ll take some preparation and luck to see it. You’ll need a telescope and the sky has to be clear.
In Pittsburgh we’ll have to cross our fingers. Our sky is usually overcast in winter.
A fast moving cold front crossed western Pennsylvania yesterday. The wind roared and temperatures fell from 61 degrees F Sunday morning to 19 degrees yesterday afternoon. The weather news called it a clipper.
Technically it’s an “Alberta clipper,” described by Wikipedia as a fast moving low pressure area that typically affects the central provinces of Canada and parts of the Upper Midwest and Great Lakes.
Clippers start as warm moist wind from the Pacific that crosses the Rockies into Alberta. When the wind hits cold air on the Canadian prairies it becomes a storm that rides the jet stream on a fast track east. By the time clippers get to Pennsylvania, Alberta is rarely mentioned.
Though clippers sweep across the continent, they’re regional so if you live outside their zone — say in California, Colorado, or Florida — the word brings to mind the fast-moving sailing ships of the mid 19th century, famous for sailing through dangerous storms at Cape Horn (above). The weather system is named for the ship.
Yesterday’s clipper left Pennsylvania but now we’re in for real winter — a low of 1 degree F Thursday morning.
Fill your bird feeders! Birds need food to survive this cold.
(Clipper Ship at Cape Horn, painting by James E. Butterworth, public domain via Wikimedia Commons. Click on the image to see the original)
Because the earth’s orbit is slightly elliptical, we’re always closest in early January and furthest in July (aphelion), a difference of about 3 million miles. This sounds like a lot but it’s tiny compared to the size of our orbit. The distance has no practical effect on our temperature.
… but …
When the earth gets close to the sun, the gravitational pull makes us speed up as you can see in the animation. Right now we’re moving about 1 km/second faster (2,237 mph) than we do in July and this does affect our seasons. The season surrounding early January (our winter) is 5 days shorter than the season surrounding early July. This is nice for us but too bad for Australia where their summer is short.
This animation shows our fast and slow progress but its real purpose is to illustrate earth’s orbital precession (in an exaggerated way).
Earth’s orbit is not a closed ellipse. Instead it tracks out a little further each time as if drawing a huge daisy in outer space without lifting its pencil. In 21,000 years we come back to where we started and trace the same daisy again.
(animation posted by WillowW on Wikimiedia Commons. Click on the image to see the original with documentation)
Today’s going to be a dark day in Pudasjärvi, Finland, where this photo was taken. Within the next 12 hours, the sun will reach its southern solstice(*).
Pudasjärvi is so far north (at 65° 22′ 39″ N, 26° 55′ 04″ E) that during the winter solstice the sun is up only 3 hours and 30 minutes, rising at 10:27am and setting at 1:58pm. At high noon it will be only 1.5 degrees above the horizon — barely risen — and to make matters worse the moon is New so it won’t provide any light at all.