This week, my son Zack has been shadowing me at work. This is an official internship that all 9th graders in France do. He talked to some other researchers in my department (the Laboratoire d’Astrophysique de Bordeaux) and visited the labs where they build cool stuff (like electronics for radiotelescopes and pieces used in space…
A group of planets can share the same, stretched-out orbit around a star. And it’s pretty extreme.
The classic sci-fi series Firefly takes place in a 5-star system called the Verse. Unfortunately, the Verse as it was originally envisioned is unstable. Let’s re-imagine the Verse — or actually, four different “Better Verses” that are stable and include all of the elements that made Firefly such a great show.
It’s time to revisit one of my favorite topics: co-orbital planetary systems, in which more than one planet share the same orbit around a star. (Side note: co-orbital systems can exist on different size scales — many stars can share an orbit around a black hole, or many moons share an orbit around a planet,…
To celebrate the opening of Avatar 2, I made a series of slides to give a little more astrophysical context to Pandora. And, like the movies, it’s all about the visuals…
Just like a doofus with the remote control bouncing between two TV shows, planets can bounce between stars in a binary system…
Here’s something brand new – we made a big splash!
A pile of free-floaters just dropped with a crash!
A hundred new rogue planets! Yup, we just found ‘em
They orbit among stars instead of around ‘em.
The time capsule must serve as a beacon. Any other civilization that detects it should immediately suspect that it is of artificial origin. And it needs to survive for countless billions of years.
This post is an adventure in world-building. I use N-body simulations to find orbital configurations of planetary systems that (I think) are completely new, pretty awesome and unexpected. It involves cohorts of co-orbital planets…
Have you ever been lost in the desert?
Stumbling along the sand dunes, the Sun beating down on you, your mouth sticky and dry. All you can think about is water…
Sometimes removing the outer atmosphere from a Neptune-like planet can reveal an ocean paradise!
A while back I wrote a series of posts called How planets die. It was about all the ways planets can be sterilized or destroyed. I even made a “planetary death scale”. Gruesome stuff. Let’s liven things up with a new mini-series on Second-Chance Planets. These are planets that get a second chance at life. …
Where would we be without the occasional asteroid crashing into the Earth?
Just like people, stars age. Their planets go along for the ride and are often killed or maimed in the process….
If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason. — Deep Thoughts by Jack Handey This series is about how planets die — it is introduced here. Earth is a cosmic freaking paradise. Just look at our neighboring planets:…
If you ever drop your keys into a river of molten lava, just let them go because, man, they’re gone. — Deep thoughts by Jack Handey This series is about how planets die — it is introduced here. What do you think of when you hear the word tides? Ocean waves? The Moon? Maybe sitting…
Gas giants have murdered rocky planets (or their building blocks) around ~5 billion stars in our galaxy! (Usually by dropping them onto their Suns!).
Just like people, planets are born and they die. We know how people die. But google “how planets die” and you’ll get the wrong answer.
Can moons orbit moons? wondered Juna and I.
Some planets have moons, you know, up in the sky
But none of those moons has its own moon around it.
When Juna’s son learned this he just was astounded!
Planets orbit stars. Moons orbit planets. But no moons have their own moons (let’s call them submoons). Why is that?
One star. Two planets share an orbit, with one following a horseshoe-shaped path around the other. Boom!
Welcome to what might very well be the culmination of the Building the Ultimate Solar System series. Teaser: the system built in this post could also be called the Ultimate Engineered Black Hole Eyeball Ringworld Solar System (if you’re really not into the whole brevity thing). Our Solar System has one habitable planet. A few…
What happens when the central body in a planetary system is replaced with a million-Sun black hole?
Planets are kind of my thing. But black holes are awesome too. I mean, they can just suck you right in… (I will never apologize for my bad jokes!) I want to bring black holes and planets together. In this post, I’ll first introduce black holes. Then we’ll build the Black Hole Solar System. In…
Gas giants are the bullies of planetary systems. They are hundreds of times more massive than small rocky or icy worlds, so when gas giants throw a tantrum, their whole planetary system feels it. Giant planet moons are among the innocent bystanders swept up in the chaos. Giant planets around other stars have different orbits…
I always thought that only 2 or 3 planets could share the same orbit. I was wrong. And it changes everything (for a super-advanced civilization, anyway).
I stumbled upon a simple way to tighten up the Ultimate Solar System. And by stumbled upon, I mean I discovered that someone else had figured it out. And I took it.
Systems of super-Earths may form as long resonant chains, most of which go unstable.
Wake up now people, I’ve got some big news! You won’t want to miss this. You don’t want to snooze. We just found some planets while we were stargazing Gather ’round, listen up. These ones are amazing! And it’s not just one new planet. There are seven! All orbiting one star up there in the…
Trojan planets are the best! I am a big fan. I love the idea of two planets sharing the same orbit around a star. To me, it’s where physics meets magic. (Remember, we’re talking planets not condoms! See here for a little refresher, and here for another article about Trojans). As a planet orbits a…
This planet and star, now, you really should know ‘em.
And that’s why I’m bothering writing this poem.
There is only one Superman. One Wonder Woman, one Captain America, one Ironman. All told, a few dozen superheroes. And billions of superhero fans. What about our Solar System? Are we one-in-a-million like Batman? Or a dime-a-dozen like Batman’s fans? How unique, how special is our Solar System? For the first time in human history,…
What happens when good planetary systems go bad….
Life is caught in a chicken-and-egg situation. For life to exist on a planet, the planet must of course have the right conditions for life. The planet must be habitable. But a planet’s habitability depends in large part on whether it already has life. It’s a lot easier for a planet with life to be habitable. So a planet needs life to be able to host life….
Carl Sagan famously called Earth the “pale blue dot”. Viewed from a large distance, that is what our complex, vibrant, living planet looks like. In the search for life around other stars, we should be looking for other pale blue dots, right? Maybe not. There is some reason to think that not all habitable planets…
Welcome to Real-life Sci-fi worlds. I use science to explore life-bearing worlds that are the settings for science fiction stories. This post is a pared-down summary of an article I wrote for Aeon in April 2015 — see the original article here. The Sun is pretty key for us here on Earth. The number one…
There are at least three aspects of the Solar System that are weird or at least unusual: No hot super-Earths. About half of stars contain a planet larger than Earth interior to Venus’ orbit. We don’t have one. That puts us in the minority. Jupiter. Only about 15% of Sun-lilke stars appear to have gas…
Welcome to Real-life Sci-fi worlds. I use science to explore life-bearing worlds that are the settings for science fiction stories. We have already taken a look at hot Eyeball planets. Today, I have a post on Nautilus’ blog about Eyeball worlds, both icy and hot. Check it out here. The article is a bit shorter…
Welcome to Real-life Sci-fi worlds. I use science to explore life-bearing worlds that are the settings for science fiction stories. Up today: can the moon of a gas giant planet — like Pandora from the movie Avatar — really be habitable? Pandora is one of the coolest-ever settings for a science fiction story. The life-bearing…
Welcome to Real-life Sci-fi worlds. I use science to explore life-bearing worlds that are the settings for science fiction stories. Up today: a desert planet like Arrakis from the classic Dune books (and the movie and miniseries). A tribute for author Frank Herbert‘s birthday (a couple days late). Dune is one of the all-time classic…
Welcome to Real-life Sci-fi worlds. We are using science to explore life-bearing worlds that are the settings for science fiction stories. Up today: an Earth-like planet orbiting a brown dwarf. Setting Planets have been found orbiting all kinds of stars. Stars like the Sun. Stars brighter and fainter than the Sun. Giant stars. Planets have…
Welcome to Real-life Sci-fi worlds. We are using science to explore life-bearing worlds that are the settings for science fiction stories. Up today: the oscillating Earth. Setting Earth’s orbit is not fixed. Gravitational kicks from the other planets change the shape of Earth’s orbit. Earth’s orbit oscillates between being perfectly circular (having an “eccentricity” of…
Welcome to Real-life Sci-fi worlds. We use science to explore life-bearing worlds that are good settings for science fiction. Up today: the hot Eyeball planet. Planets very close to their stars are too hot for life, right? Well, not always! Take the Earth and move it closer and closer to the Sun. It gets hotter…
Welcome to Real-life Sci-fi worlds. We are using science to explore life-bearing worlds that are good settings for science fiction. Let’s take the Earth and change just one small characteristic: the shape of its orbit. Setting. Earth’s orbit is nearly a perfect circle. Earth is always the same distance from the Sun (to within a…
A desert world with two suns in the sky. The jungle-covered moon of a gas giant planet. A planet completely enveloped in ice. A stormy ocean-covered world. A planet infested with bubbling lava fields. These are the settings for science fiction stories. They paint pictures of other worlds. Where life can exist but things are…
Giraffes are covered in patches. The patches are brown and the space in between the patches is white. Everyone knows this. Here is something you probably didn’t know: you can see those patches in infrared light. In simple terms, infrared light measures heat (at least at the temperatures we are used to in everyday life). …
We are building the ultimate Solar System. In Part 1 we chose the right star. In Part 2 we chose the right planets. In Part 3 we chose the right orbits for the planets. In Part 4 we learned two ninja moves about how more than one planet/moon can share the same orbit. Today’s…
We are building the ultimate Solar System. In Part 1 we chose the right star. In Part 2 we chose the right planets. In Part 3 we chose the right orbits for the planets. Today’s job: Discovering two ninja moves that will allow us to pack way more worlds in the habitable zone. The…
We are building the ultimate Solar System. In Part 1 we chose the right star. In Part 2 we chose the right planets. Today’s job: choosing the right orbits for the planets. Let’s get started. Our goal is simple. We want to pack as many planets into our star’s habitable zone as possible. We…
We are building the ultimate Solar System. In Part 1 we chose the right star. Today’s job: choosing the right planets to put in our ultimate Solar System. Let’s stick to two defining characteristics: a planet’s size (or mass) and its composition. We want Goldilocks-ish planets. They shouldn’t be too small, too big, too…
We are building the ultimate Solar System. Here is an introduction to the game. What kind of star will anchor our ultimate Solar System? It comes down to two choices: stars like the Sun or cooler, redder stars sometimes called “cool stars” or “red dwarfs”. Why not stars bigger than the Sun? Because they…
A while back I performed an experiment called build a better Solar System. The game was to make better use of the Solar System’s habitable real estate. In the game I was required to keep all of the Solar System’s planets (and large moons) and their orbital configurations. Just by switching the orbits of different…
That spanking new planet’s already a star. K-186 f, you know who you are. You’re making us wonder if we’re all alone. The planet out there in the habitable zone. I’ve been on the radio. Been on TV. Talking ‘bout the planet. Just what can we see? Just what do we know about this special…
In the spirit of last week’s poetic post, here are two more stanzas for your reading pleasure…. There is a new exoplanet in town. This planet has only just now been found. Why should you care? It’s only one more. Well this is one planet we’d love to explore. This planet’s orbit is really just…
We’ve discussed some classes of planet that are pretty strange: hot super-Earths, hot Jupiters and eccentric gas giants. But that was just the warm-up. In this post we’ll check out three more extra-weird ones. First up: Tatoine planets. In case you are less nerdy than you should be, Tatooine is where Luke came from in…
We have a lot of weird neighbors. By neighbors I mean planets orbiting other stars. And by weird I mean that most of the extra-solar planets that we know look a lot different than the planets in the Solar System. To start with, let’s take a look at our neighbors’ houses. By houses I mean…
Oceans cover 71% of our planet. About 60% of the human body is water (more for kids, less for adults). Beer is 90-97% water. But, on a global scale, Earth is actually very dry. Earth is only about 0.1% water by weight. If all of Earth’s water were smushed into a ball it wouldn’t even…
[This post is co-written by Franck Selsis] Where should we look for extra-solar life? In a star’s habitable zone of course! Any planet in that magical Goldilocks zone must host life, right? Well, not exactly. The habitable zone should really be called the liquid water zone. A planet with the right characteristics that orbits its…
One of the most exciting recent things that I’ve worked on recently — with colleagues in France and the US — is a new model for how the Solar System formed that we call the Grand Tack. “Why do we need a new model for how the Solar System formed?”, you might ask. “What was…
[UPDATE: a new series on building the ultimate Solar System starts here] The Solar System is a disappointment. It does contain an inhabited planet with forests and oceans and frisbees and beer (Earth). But it only has one. There are a couple worlds with some potential, but they are pretty disappointing too. Jupiter’s moons Europa…
A primary theme of this blog is to explore the different processes that affect the existence and evolution of planets that could harbor life. Today’s question: Are binary stars good or bad? Short answer: BAD, but not in all cases or for the reasons you might expect. (Jump to the end for a quick summary…