If It’s Clear, Check Out the Geminid Meteor Shower!
The Geminid Meteor shower. Courtesy Asim Patel, CC By-SA3.0
The last major meteor shower of the year happens this weekend — the Geminids — fly again! The peak is Sunday morning (in the very wee hours!) but you can likely start seeing the shower’s meteors starting early Saturday. If you’re up and around, and it’s clear out — check ’em out! You could see a few meteors per minute, appearing to stream from the direction of the constellation Gemini.
Where Do The Geminids Come From?
The Geminids, like all meteor showers, are created as pieces of comet or asteroid grains slam through our atmosphere. On the way down, they vaporize due to friction with ouratmospheric gases. What you see as a meteor is that vaporization — literally a bit of solar system history being destroyed before your eyes.
The Geminids are created by bits of debris that stream away from the asteroid 3200 Phaethon. As it orbits the Sun, it leaves bits of itself behind. Earth plows into that stream of material each December. Since asteroids date back to the earliest times in solar system history, the bits it leaves behind and that collide with Earth’s atmosphere literally ARE history going up in vapor!
3200 Phaethon
This parent asteroid to the Geminids is pretty unusual. It has a very elliptical orbit that brings it much closer to the Sun than many of the known asteroids in similar orbits. it was discovered in images taken by the Infrared Astronomical Satellite in 1983 — the first ever asteroid to be so detected. Once its orbit was determined, it didn’t take long for astronomers, led by Fred Whipple, to figure out it was the source of the Geminid meteor shower. So, while you’re out enjoying the Geminids this weekend, take a moment to savor the history that’s being made (and ended) before your eyes!
This mosaic is composed of the sharpest views of Pluto that NASA’s New Horizons spacecraft obtained during its flyby of the distant planet on July 14, 2015. The pictures are part of a sequence taken near New Horizons’ closest approach to Pluto, with resolutions of about 250-280 feet (77-85 meters) per pixel. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The New Horizons mission has been steadily returning its treasure trove of images from the July 2015 flyby. Today’s image release showed just WHY it was important to send a darned good camera/detector along for the ride! It’s even more amazing than the “snakeskin Pluto” images I wrote about earlier!
Feast your eyes on this strip image of Pluto’s surface. Go ahead, click on it. Zoom into it and really check out all the features. I am particularly intrigued by the “dune-ish” looking features in the lower part of the image. These are giant ice blocks bounded by the al-Idrisi Mountains that border Sputnik Planum. The “dunes” are not wind-driven piles of sand as they would be here on Earth. These rippled surface features form as the nitrogen-rich ices on the surface undergo some kind of heating that causes the ices to sublimate (think of dry ice sizzling in the sunlight here on Earth).
Also, check out those mountains! They’re made of water ice and jutting up above the surface. Pluto’s highlands form a sort of “shoreline” that rises above Sputnik Planum. Notice that some of the mountainsides are bright while others appear to be darkened by something. As Alan Stern said during the flyby, “Who ordered THAT?”
If you’re a crater fan, there are plenty of them on Pluto’s surface. But, there are also some strange-looking crater-type formations that are probably more like sunken pits. They could be the result of subsurface activity. Maybe something heated the ice from below, causing it to soften and then subside (sink in on itself). Some of those mountains you see could be ice volcanoes, too. They would definitely require some kind of heating from below to start the flow of “molten” ice up to the surface.
Just to give you a sense of scale, the image strip covers a region about 50 miles (80 kilometers) across, spanning from the mountains to the heart of Sputnik Planum. The smallest features are about the size of half a city block. As you scan the image you’ll find craters, mountains, glacial features, and some rugged areas called badlands.
This is the kind of visual exploration planetary scientists love to do if they can’t get to the surface of a world themselves. You can spend a lot of time poring over this image and thinking about how wonderful, weird, and fascinating the 9th planet really is!
What amazes me is that all of this that you’re seeing is ice. That’s not surprising in itself. Pluto is an icy-surfaced world, which we pretty much knew going in. However, the sheer variety of this world’s surface features remained unknown until the New Horizons flyby. We’re just starting to see what a complex surface this planet has.
To put this accomplishment into perspective, the spacecraft traveled nearly three billion miles (about 5 billion kilometers) for nearly 10 years and is returning high-resolution images five times better than the images returned by Voyager 2 of Pluto’s icy cousin world Triton (which orbits Neptune).
We live in amazing times, folks. Why? Because, you can see things like this courtesy of a little spacecraft not much bigger than a grand piano!
Enjoy — and, when you’re done here, check out more images and a great little movie, over at the New Horizons team Web site!
