Happy Anniversary Exoplanets

This month is the twentieth anniversary of the discovery of exoplanets, which are really just planets that are not in our solar system. (Frankly, I dislike the term exoplanet. It is so solarcentric.)

When you think about it, the discovery of planets outside our solar system (we need a word for that) is a special thing. On a graph of how expected and mundane a scientific discovery is vs. how exciting a scientific discovery is, these planets are distant outliers.

Screen Shot 2015-11-19 at 11.55.55 AM

For years astronomers and cosmologists and others assumed that stars would generally have planets around them, or at least, this would often be the case. This is all part of the famous Drake Equation, best stated by Carl Sagan using the word "Billions" (with two b's) over and over again. Like this.

OK, he didn't really use "Billions" a bunch of times. But he might have.

Anyway, Nature.com has a nice set of infographics on the topic, one of which I've posted above. The rest are here.

More like this

"Continue to surprise those who would put you in a neat demographic. Be insistently curious." -Gordon Gee Twenty years ago, our Solar System was the only one we knew of that we were certain had planets orbiting around a main-sequence star. Image credit: retrieved from Universe-Review.ca. Perhaps…
If you missed the first (or later any) episode of Cosmos 2014, you can get it on Amazon Prime streaming (for a fee). It's worth it. Here are a few comments I jotted down (then lightly edited) while watching the first episode. Neil does have his own spaceship, like Carl did. That's important…
"Death comes to all, but great achievements build a monument which shall endure until the sun grows cold." -Ralph Waldo Emerson In the great cosmic ocean, there's only one planet that we know -- for certain -- has the right conditions and history to result in intelligent life: our own. Image…
By Franck Marchis There will be a before and after Kepler Era in astronomy. Today, with the release of 1,202 exoplanet candidates from data collected with the Kepler spacecraft over 140 days of observation, we have just entered in a new age of astronomy. The Kepler spacecraft is the 10th NASA…

I think the words are "another planet,"

By Theo Dzielak (not verified) on 19 Nov 2015 #permalink

Hate to be too pedantic and its a minor thing but actually the first exoplanets (& I agree about that word*) were found in 1991-2 around the Pulsar PSR B1257+12 (See : https://en.wikipedia.org/wiki/PSR_B1257%2B12 ) by Aleksander Wolszczan and Dale Frail.

As a sidenote, I think there were also competing claims of an earlier planet or brown dwarf around another star the orange giant Gamma Cephei or Errai A which was thought to exist in 19988 but not have a strongly proven enough case until later studies confirmed it's existence.

There is also "Latham's planet" or HD 114762 b which may be a superjovian world or a brown dwarf depending one its exact unknown orbital inclination found in 1989 around an F9 type Procyonese - but low "metalicity" subdwarf - star.

So, its complicated but basically yeah except for the pulsar planets!

Still great article though.


* The IAU definition of planet among many other severe flaws breaches the Copernican principle by stating all planets must orbit our sun which is frankly ridiculous.

SteveR, that seems right.

Here's what they say specifically:

"Twenty years ago this month, astronomers announced the discovery of 51 Pegasi b, the first confirmed planet orbiting a Sun-like star. The hellish gas giant orbits just beyond the searing heat of its parent star, and it opened astronomers’ eyes to the astonishing range of alien worlds that exist throughout the Galaxy."

So maybe they have a specific definition of "confirmed" in mind.
"The IAU definition of planet among many other severe flaws breaches the Copernican principle by stating all planets must orbit our sun which is frankly ridiculous."


Pedantic...someone has been watching too much of Sheldon Cooper on the Big Bang Therory

By Dr. Mark Feiler (not verified) on 24 Nov 2015 #permalink