

Exoplanet discovery count by year - cryptoz
http://exoplanet.eu/diagrams/?t=h&f=&x=discovered&xmin=&xmax=&y=raw&ymin=&ymax=

======
Jun8
When I saw this on HN, I rewatched the _Cosmos_ episode ("The Backbone of the
Night", aired on Nov 1980) where Carl Sagan is lecturing sixth graders in a
Brooklyn school (the one he attended as a kid) on techniques to search for
exoplanets and then says (from <http://www.american-
buddha.com/backbone.night.htm>):

Well, both of these methods are being used, and by the time that you people
are as old as I am, we should know for all the nearest stars whether they have
planets going around them or not. We might know dozens or even hundreds of
other planetary systems and see if they are like our own, or very different,
or no other planets going around other stars at all. That will happen in your
lifetime, and it will be the first time in the history of the world that
anybody found out really if there are planets around other stars.

His stress on "even hundreds" shows that even he thought this figure was
unlikely. Sagan was 47 at that time, so assuming the kids were about 12, he
was hypothesizing into 35 years to the future, to 2015. He would have been
pleasantly surprised at the progress so far, I think.

I wonder if any one of those kids have looked at this page and thought of that
day.

~~~
InclinedPlane
The amazing thing is that he was more optimistic than most astronomers at the
time with regards to extrasolar planets. It's a funny thing, prior to the
mid-1990s there had only been extremely incomplete searches for exoplanets,
and they all came up negative. But if you looked at the search space of those
studies you see right away that they were really quite pitiful. I suppose this
is one of those "effort trumps reason" situations, as a lot of effort were put
into searches though they had almost no hope of finding planets. And yet those
efforts led to a bias against the idea that planet formation could be common,
and a bias against the scientific value of looking for planets.

At the onset of the great exoplanet discovery breakthrough in the mid '90s
only a few very meagerly funded teams working were actually searching. Once
they started to find planets then the astronomical community started paying
attention, and funding as well as access to the best observatories in the
world started pouring in.

Also, an interesting point of fact is that Sagan was actually hugely
excessively optimistic. The two techniques for exoplanet discovery he
describes are direct observation through occultation or deep nulling of
stellar light and astrometry. As it turns out, these techniques are very, very
difficult to use and we have not actually built any special-purpose spacecraft
that use either method. To date only one planet has been detected through
astrometry, for example. But there are methods which work rather well (doppler
radial velocity and transit detection) though they were not familiar to Sagan.

------
pjungwir
From what I understand, most known exoplanets are gas giants, and almost all
orbit their sun at about the distance of Mercury, because those are easier to
detect. That leaves a lot of harder-to-see exoplanets we can only guess at.
There are about 20 stars within a dozen light years, so I wish we could send
probes to them and take a closer look. It would be a gift to our
grandchildren. The risk is that in the time they would take to get there, our
detection capabilities may have improved so much they'd wind up being useless,
but I sort of doubt it. Being 7-12 light years closer has got to make a
difference.

EDIT: Here is an amazing video showing all known exoplanets orbiting one star,
so you can see their relative sizes, distances, etc.:

<http://vimeo.com/47408739>

~~~
typpo
Here is a similar visualization in webgl, superimposed on our solar system for
reference: <http://www.asterank.com/exoplanets>

Nearly every single exoplanet discovered is within the orbit of Mercury.

------
cryptoz
These are confirmed exoplanets, totalling 872 so far. Kepler and other
missions have found probably tens of thousands more planets that are in
unconfirmed status and will take years to confirm. If I may speculate, and
take SpaceX and Planetary Resources to be successful 10 years out, we might be
able to build absolutely astonishingly large telescopes to resolve continent-
scale features on exoplanets - and have discovered and mapped millions of them
in the Milky Way.

~~~
joshuahedlund
By "confirmed" do you mean we've directly observed the planets as opposed to
calculating that they exist due to changes in the light from their stars?
Regardless I'm very excited about increasing our understanding of these
planets.. Sounds like NASA is planning to launch a telescope specifically for
discovering more about planets as well[1]

[1][http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-088_Astro_Exp...](http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-088_Astro_Explorer_Mission_.html)

~~~
svachalek
I believe confirmation is usually just a process of double-checking data and
waiting to see a regular cycle of wobbles or occultations. Directly observing
a planet with current telescopes is difficult but it has been done:

[http://en.wikipedia.org/wiki/Category:Exoplanets_detected_by...](http://en.wikipedia.org/wiki/Category:Exoplanets_detected_by_direct_imaging)

------
nealabq
Nice illustration. But the x-axis scaling seems a bit wrong to me. Like
there's only 8 or 9 years in each decade.

------
arscan
Not to be that guy, but the fact that it plots 2013 and 2014 really messes up
the impact of this chart. When I first saw it, I was thinking "whoa, we must
have severely cut funding for such a huge dropoff!"

~~~
cryptoz
It just takes an extra bit of thought, that's all; look at the 2013 value and
then remember it's only _April_. Then think about what 2014 might look like.

Edit: Here's the graph just up to 2012:
[http://exoplanet.eu/diagrams/?t=h&f=&x=discovered...](http://exoplanet.eu/diagrams/?t=h&f=&x=discovered&xmin=1985&xmax=2012&y=raw&ymin=&ymax=)

~~~
Wintamute
2012 shows a drop down to about 150 from 200 in 2011. So there is a drop off.
I think? Or perhaps the graph is just horrible, it's very hard to tell.

------
pjungwir
Does anyone know if exoplanets can find a stable orbit around binary stars? I
read recently that 50-80% of stars are multi-star systems. It seems like it'd
be hard for planets even to form with such a varying magnetic field.

~~~
Martimus
Yes, actually, and some have recently been found.
[http://phys.org/news/2013-03-capture-picture-tatooine-
planet...](http://phys.org/news/2013-03-capture-picture-tatooine-planet-
orbiting.html)

------
3327
e^x

~~~
nealabq
Just eyeballing, but I don't think there's enough data to call that
exponential growth. And the log plot doesn't look like it's fitting a straight
line -- it's curving down a bit at the end.

------
maeon3
By the time we achieve technology where it is feasible for our species to
utilize these exoplanets we will have sufficient technology for humanity to
live normal lives without planets altogether.

The future of our species is huddling around the warmth of the campfire (sun)
and using raw materials from the asteroid belt to create structures orbiting
the sun, until we create a sphere around the sun and all space is exhausted...
then.. maybe after another few hundreds after that point, will these planets
become useful. But not for reasons we would think. Perhaps for research
purposes to see if humans then have the capability to tune back in to
evolution after a thousand years of being pampered and letting the DNA
deteriorate by eliminating survival of the fittest.

