Up for a meteor shower? Good, because there’s one starting now, called the Geminid Meteor Shower. It actually takes place starting around the 7th of December and peaks around the 13th or 14th. It’s called the “Geminid” shower because the meteors it delivers to Earth’s atmosphere seem to radiate from the constellation Gemini. Think of it like driving through a dust cloud or a snowstorm and seeing particles coming at you from the same point just ahead.

In a good year, observers may see up to 120 Geminid meteors per hour. However, this year, it may not be so great because of moonlight. The Moon is just past full (it’s waning gibbous). That means the skies will be brightened by moonlight, which will wash out the dimmer meteors. But, it’s still worth checking out because the shower usually does deliver some bright meteors. If you do go out, dress warmly, and try to find a location where you can stand to block out the Moon. They’re definitely worth checking out and if you want more info on what you might see, check out about viewing conditions.

What Causes the Geminids?

Meteor showers originate in swarms of ice, bits of dust, and pieces
of rock the size of small pebbles that exist in the solar system in streams. Where does all that solar system flotsam come from? Most of it streams away from comets as they orbit the Sun. As they get closer to our star, their icy cores get warmed up. That causes the cometary nucleus to lose material. Eventually, all that debris spreads out along the path of the comet. Some streams also come from asteroids.

Most of the time, all that debris stays in space. But, in certain times of the year, Earth intersects those streams as it pursues its own orbit around the Sun. There are about 21 or so that it does encounter. They are the sources of the best-known meteor showers we can observe. They occur when the cometary and asteroid debris slams into our atmosphere. The friction between the pieces of rock and dust and the gases in our atmosphere heats up the debris. Most of the time that’s enough to vaporize these bits of ice and rock well before they reach the ground. When that happens, we see a meteor. If a piece of the meteoroid happens to survive the trip and falls to the ground, we call that a meteorite.

In fact, the Geminids themselves are the product of the asteroid 3200 Phaethon. Although it’s a rocky body, it also ejects material as it makes its way around the Sun each year. Earth intersects its swarm of debris during the first three weeks of December every year. That intersection point happens to be lined up against the Gemini constellation. That’s why its meteors appear to come from that direction.

Watching the Geminid Shower

For folks in the colder parts of the Northern Hemisphere, catching the Geminids is an exercise in staying warm. One year, I viewed the Leonids (in November) from our front yard in Massachusetts. It was pretty cold. So, I had the idea of running my car for a few moments and then lying on the warmed hood. That’s not terribly fuel-efficient, so I don’t recommend it. In more recent years, I just dressed very warmly. Sometimes, I have a lawn chair to relax in and simply gaze at the sky waiting for meteors.

The best viewing hours are usually after midnight. That’s when Gemini is higher in the sky. However, those can also be the coldest times. So, bundle up and take a warm beverage out with you! While you’re viewing, check out the colors of the meteors you see. Each color (blue, red, white, etc.) indicates a different chemical element that is being heated as the meteor heads through our atmosphere. I’ve written about this shower before, and am always interested to see how good it will be each year.

Life Imitates Art?

Remember the movie Interstellar? It portrayed an adventure involving a black hole, some planets, and an intrepid crew who traveled via the black hole to rescue some scientists on the “other side”. While it had some obvious gaffes in the story, the science was more or less vetted by physicist Kip Thorne. He described his thought process in the book The Science of Interstellar, which I bought as soon as I got home from the movie. It was interesting to read about the interactions he had with the filmmakers, as well as the decisions he had to make to help them tell their story. ‘

One of the planets in the movie is situated near a black hole, and that proximity alters time and space not just for the region around the singularity, but for the planet itself. Dr. Thorne finds a way to scientifically justify the action on and near the planet, which makes the story all the more interesting.

Could a Planet and Black Holes Co-Exist?

I thought about that book when I saw a recent story about Japanese astronomers postulating the formation of planets around black holes. At first glance, I thought, “That’s gotta be impossible.” But, as it turns out, the possibility of planets forming around such monsters isn’t all that far-fetched. I’m a sucker for black holes (excuse the pun) because they’re just such fascinating objects. It’s why I notice stories about them and often write about these monsters.

Think about what you need to form planets: a cloud of dust and gas and an energy source. Throw in some magnetic field action, and other activities that would stir up a disk of material and you have a planet-making machine. Of course, all the planets we KNOW about have formed around stars. But, nothing says they can’t form in other places with the proper materials. And, that, according to professor Eiichiro Kokubo of the National Astronomical Observatory of Japan, could result in tens of thousands of massive planets orbiting safely outside the event horizon of a black hole. How massive? Probably ten times the mass of planet Earth, according to the professor.

Black Holes and Planets, Oh My

What kind of black holes could support such planet-building activity? In the computer models that Professor Kokubo did, supermassive black holes are good candidates. Some of them are surrounded by disks that could have a hundred thousand solar masses of dust. To put it in perspective, that is about a billion times the dust mass of a typical protoplanetary disk.

Conditions around the black hole do, of course, have to be supportive of planetary formation. In a typical protoplanetary disk, planet formation takes place in low-temperature regions where icy dust grains collide and stick together. They make sort of “fluffy” clumps that eventually collide to make bigger “pieces” of planets. The process continues to make bigger and bigger objects until planets are born.

So, could such a region exist around a black hole? Probably so. Here’s why. First of all, the central region around a black hole emits a large amount of energy. And, you’d think that radiation would destroy any chances for planets to form. However, the dust disk is very dense, and that can block the radiation. So, Kokuba and the team of researchers at NAOJ applied typical planetary formation theory to those black hole disks and it turns out it could work!

The models show that low-temperature regions could exist where ices could exist. Those places could allow the formation of those “fluffy” clumps that are the seeds of planetary formation. If it actually works, planets could form in a few hundred million years.

Black Holes and Planets and Possibilities

Nobody has found those planets yet, but theoretically, they could exist — and I would bet, in reality, they’re out there. It could be the start of a new section of planetary science, which would be pretty cool. The next thing to think about is what those planets would be like? Would they be able to support life? All interesting things to consider!