Kepler's astounding haul of multiple-planet systems

May 24, 2011
NASA's Kepler spacecraft has discovered 170 planetary systems containing between two and six transiting planets. This animation shows all the multiple-planet systems discovered by Kepler as of 2/2/2011; orbits go through the entire mission (3.5 years). Hot colors to cool colors (red to yellow to green to cyan to blue to gray) are big planets to smaller planets, relative to the other planets in the system. Credit: Daniel Fabrycky

(PhysOrg.com) -- NASA's Kepler spacecraft is proving itself to be a prolific planet hunter. Within just the first four months of data, astronomers have found evidence for more than 1,200 planetary candidates. Of those, 408 reside in systems containing two or more planets, and most of those look very different than our solar system.

In particular, the Kepler systems with multiple are much flatter than our . They have to be for Kepler to spot them. Kepler watches for a planet to cross in front of its star, blocking a tiny fraction of the star's light. By measuring how much the star dims during such a transit, astronomers can calculate the planet's size, and by observing the time between successive events they can derive the - how long it takes the planet to revolve around its star.

To see a transit, the planet's orbit must be edge-on to our line of sight. To see multiple transiting planets, they all must be edge-on (or nearly so).

"We didn't anticipate that we would find so many multiple-transit systems. We thought we might see two or three. Instead, we found more than 100," said Smithsonian astronomer David Latham (Harvard-Smithsonian Center for Astrophysics).

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Latham presented the findings today in a press conference at the 218th meeting of the American Astronomical Society.

In our solar system, some planet orbits are tilted by up to 7 degrees, meaning that an alien astronomer looking for transits wouldn't be able to detect all eight planets. (In particular, they would miss Mercury and Venus.) The systems spotted by Kepler are much flatter, with orbits tilted less than 1 degree.

Why are they so flat? One clue comes from the planets themselves. The multiplanet systems found by Kepler are dominated by planets smaller than Neptune. They lack Jupiter-sized . Scientists believe that a gas giant's powerful gravity tends to disrupt , tilting the orbits of neighboring worlds.

"Jupiters are the 800-pound gorillas stirring things up during the early history of these systems," explained Latham. "Other studies have found plenty of systems with big planets, but they're not flat."

Multiple-planet systems may offer a chance for confirming the densities of small, rocky worlds. The more massive a planet, the easier it is to detect using radial velocity measurements (essentially the star's wobble as a planet's gravity tugs it). Earth-sized worlds in Earth-sized orbits aren't massive enough to make a radial velocity signal that's detectable with present technology.

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In systems with more than one transiting planet, astronomers have another option: transit timing variations. They can measure how the time between successive transits changes from orbit to orbit due to mutual gravitational interactions between the planets. The size of the effect depends on the planets' masses.

"These planets are pulling and pushing on each other, and we can measure that," said Smithsonian astronomer Matthew Holman. "Dozens of the systems Kepler found show signs of transit timing variations."

As Kepler continues to gather data, it will be able to spot planets with wider orbits, including some in the habitable zones of their stars. Transit timing variations may play a key role in confirming the first rocky planets with the right temperature for water to be liquid on their surfaces.

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eachus
5 / 5 (5) May 24, 2011
Why are all the multi-planet systems found by Kepler flat? Because Kepler can only find flat systems. Duh! (Well, there is also the possibility that Earth is close to or on the line where the planes of two planets orbits intersect. But Kepler would see that as a flat system.) Is it possible that there are undiscovered planets in these systems which are not co-planar with the other planets? Sure. But unless they are massive, they will be undetectable for now.
Newbeak
4.3 / 5 (7) May 24, 2011
The corollary is that stars with planets are as common as dirt,which increases the odds for extraterrestrial life.
that_guy
5 / 5 (2) May 24, 2011
I kinda wonder how many planets are in your average system...or even if systems with more planets than ours is common.

Can you imagine taking a trip through the delta IV system with 34 planets available to see?

actually, slightly more serious, have they done a model on how many planets a system can hold in stable config?
kevinrtrs
1.3 / 5 (24) May 24, 2011
The corollary is that stars with planets are as common as dirt,which increases the odds for extraterrestrial life

Under what conditions would this statement hold? If you regard the occurrence of life as a spontaneous random variable then certainly the odds would increase.
Except that life as we know it has the distinct appearance of not being a randomly occurring event, but rather a specific, planned and highly organised affair. Hence finding more planets would not necessarily increase the chances of finding life out there.
that_guy
4.2 / 5 (11) May 24, 2011
Kevin, your statement is completely invalid. Unless the absolute chances of life on another planet are exactly 0%, then a higher incidence of planets necessarily means an increased chance of the incidence of life.

...And that said...nowhere in the bible does it say that there are only humans and angels. In fact it strongly implies that there are other creations/creatures on other planets. The ONLY thing that it implies (Though does not state directly) is that we are the only planet with the good/evil sin dichotomy/battle.

So which way would you like to be wrong, mathematically, philosophically, or biblically?
SemiNerd
4.7 / 5 (19) May 24, 2011
kevinrts - Intelligent design is not science. It simply begs the question of the origin of life, because if there was a creator, who created the creator?

And 'its turtles all the way down' isn't a valid answer.

Please stop making religious posts on a scientific forum.
SemiNerd
4.5 / 5 (2) May 24, 2011
I kinda wonder how many planets are in your average system...or even if systems with more planets than ours is common.

Can you imagine taking a trip through the delta IV system with 34 planets available to see?

actually, slightly more serious, have they done a model on how many planets a system can hold in stable config?

Its really unlikely, because unless planets are pretty small, the closer they get to one another the more chances they have of disturbing each others orbit. This either causes collisions or ejection from the suns gravity.
that_guy
4.5 / 5 (2) May 24, 2011
That many planets may be unlikely, but it seems that planets should be able to orbit significantly beyond where our 8 planets end. (There have been some large exoplanets found beyond the orbital distance of neptune), and if a system had smaller planets, it appears that they would be able to have closer orbits, for example, if we didn't have jupiter, we would likely have another rocky planet at the asteroid belt.

I think that it's still a valid question, what is the highest number of planets that we are likely to find in a stable configuration? kepler is showing us that there are oodles of multi-planet systems to find, even with our extremely limited methods and means.
Newbeak
4.9 / 5 (7) May 24, 2011
The corollary is that stars with planets are as common as dirt,which increases the odds for extraterrestrial life

Under what conditions would this statement hold? If you regard the occurrence of life as a spontaneous random variable then certainly the odds would increase.
Except that life as we know it has the distinct appearance of not being a randomly occurring event, but rather a specific, planned and highly organised affair. Hence finding more planets would not necessarily increase the chances of finding life out there.

Yes,that is what I meant.The more planets there are,the greater the odds that some of them are amenable to the evolution of life.
As far as life here having the "distinct appearance",as you put it,of being planned,I don't want to get into religious arguments on a website for disseminating scientific ideas.Suffice to say that the recent work of Craig Venter et al has demonstrated that life can be created from inanimate chemicals.
spectator
3.3 / 5 (3) May 24, 2011
That many planets may be unlikely, but it seems that planets should be able to orbit significantly beyond where our 8 planets end. (There have been some large exoplanets found beyond the orbital distance of neptune), and if a system had smaller planets, it appears that they would be able to have closer orbits, for example, if we didn't have jupiter, we would likely have another rocky planet at the asteroid belt.

I think that it's still a valid question, what is the highest number of planets that we are likely to find in a stable configuration? kepler is showing us that there are oodles of multi-planet systems to find, even with our extremely limited methods and means.


The number of satellites in a system is limited not only by the mass of the satellites, but also harmonics.
spectator
1 / 5 (11) May 24, 2011
The ONLY thing that it implies (Though does not state directly) is that we are the only planet with the good/evil sin dichotomy/battle.


Would have to disagree.

Several passages in the Bible indicate that the angels in heaven are both good and evil. In fact, it is evident that Satan has never yet been forbidden access to heaven, as that doesn't actually happen until around the time of the millenial.

The point I'm getting at is that, at least as far as the Bible explains, every being that God has ever made has free will and consequently has the same moral dilemma.

The only defense I can offer for atheists is that they rebel out of ignorance, plus even God himself said humans can't help it because they are evil from their youth since the fall, but the fallen angels rebelled knowingly. So in that sense one could say that few humans could possibly be considered as evil or as guilty as some of these "persons," whoever and whatever they are.
spectator
1 / 5 (10) May 24, 2011
Although you are partly correct.

There are at least 9 different types of angels described in the Bible, ranging in appears to identical to a man such that a human observer can't even tell the difference until they were told so, up to more exotic creatures.

Thus if you want to call them "alien," that is a fair statement, because they are not of this world, but in exactly what way they are "alien" is not entirely clear. They are presumably "Spirit" beings, but is also clear from the Bible that they have physical bodies, humanoid and/or demi-human form, and in a few cases even eat physical human food.

But as far as being something that inhabits some other "planet," there is no indication of that in the Bible, even though there IS indication in the Bible that in New Testament times, they KNEW there were other "worlds" in the universe besides Earth.

In the Bible, the angels are seen to inhabit a spiritual plane called "heaven."
jmcanoy1860
4.8 / 5 (6) May 24, 2011

Under what conditions would this statement hold? If you regard the occurrence of life as a spontaneous random variable then certainly the odds would increase.
Except that life as we know it has the distinct appearance of not being a randomly occurring event, but rather a specific, planned and highly organised affair. Hence finding more planets would not necessarily increase the chances of finding life out there.


Except the presence of life can be accounted for by simple chemistry and physics and is therefore by definition not random and highly organized. You keep acting as though you have evidence for something such as a god. The problem is that in order for your assertions to hold water eventually you have to insert some version of "magic space man sez abra cadabra and poof". That isn't an explanation for anything it's just stupid. Shouldn't you have been raptured btw?
that_guy
not rated yet May 24, 2011
QC - according to the bible, the 'evil' angels were cast out of heaven to the earth, in genesis. No where did it say god let them back in. and last I checked nobody said heaven was a planet either.

I suppose in your view, atheists rebel from religion out of ignorance, but from the atheist view, they believe that there is no evidence to convince them of a deity. But what about the hindus and buddhists and shintoists?

The bible does not describe non angel beings - and pardon me for not looking it up, but there are definitely places where the wording strongly implies that god created beings other than angels or those on earth - but it is not focussed on obviously, because it is tertiary to the point of the bible.

And for my purposes, any being that primarily resides on another planet would be 'alien' - granted our biblical discussion here doesn't really apply to the article at hand anymore.
that_guy
not rated yet May 24, 2011
I think if you read genesis, daniel, and revelations with the idea of aliens in mind, you would find it to be a fascinating thought experiment, although not one for physorg. The only reason I brought the biblical stuff in my first comment, is because I knew that Kevin's comments tend to be extremely religiously inclined, so i was trying to shut his comment down on his level as well as the scientific one.
Bigblumpkin36
5 / 5 (1) May 24, 2011
go science boo bible its tale talls, What if Paul Bunyan and the blue ox were in the bible would people some how twist the thought they were planets, Yeah Science rules
antialias
not rated yet May 24, 2011
I think that it's still a valid question, what is the highest number of planets that we are likely to find in a stable configuration?

Depends on what type of planets you have. As someone pointed out: Harmonics may disrupt a system. But that comes into play more if the planets in question are massive.

So the answer depends on:
- how massive the individual planets are (I would think that more small planets could coexist and fewer if you have a few larger ones in the bunch)
- How massive the sun is (a more massive sun could have a larger solar system since its gravitational effect could bind planets further out)
- Co-planar systems are possibly stable with more planets than those which are not co-planar

IIRC there's also an equation that sets the relationships of the radii of where individual planets should be if they are coplanar. By that formula there should be (or better: should have been) another planet where the asteroid belt is. But for some reason that never came together.
yyz
5 / 5 (2) May 24, 2011
@antialias,

"IIRC there's also an equation that sets the relationships of the radii of where individual planets should be if they are coplanar. By that formula there should be (or better: should have been) another planet where the asteroid belt is. But for some reason that never came together."

Are you possibly referring to the Titius-Bode law: http://en.wikiped...%27s_law
antialias
5 / 5 (1) May 24, 2011
Are you possibly referring to the Titius-Bode law:

Yes, though that seems to be disputed and fails at larger distances from the sun. It also doesn't account for possibly captured planets.
Jotaf
5 / 5 (2) May 24, 2011
It would be very interesting to calculate/simulate the distribution of planets with stable orbits. Although very minor perturbations in the initial conditions would give radically different configurations, the final distribution across a large number of samples may be something recognizable, and if it fits a simple function it would be pretty cool.
woofwoofwoofoioioi
not rated yet May 25, 2011
OK - the Kepler systems are much flatter than ours, but they are not truly flat. They're shaped liked a Sherrin.
Mayday
not rated yet May 25, 2011
The video of the orrery is outstanding. I wish there was a Kepler app that would keep the animated orrery updated.
that_guy
5 / 5 (1) May 25, 2011
OK - the Kepler systems are much flatter than ours, but they are not truly flat. They're shaped liked a Sherrin.

I guess the australians have joined the debate. It's like a rounded football. I had to look it up to ensure that there were no cultural misunderstandings :)
yyz
not rated yet May 26, 2011
"The video of the orrery is outstanding."

Mayday & others should check out a higher-res, 720p, version of this video here: http://www.youtub...30fkyiU4

It really IS sweet.
Monshat
not rated yet May 29, 2011
Quote: "There are at least 9 different types of angels described in the Bible, ranging in appears to identical to a man such that a human observer can't even tell the difference until they were told so, up to more exotic creatures."

And don't forget the 72 houris for each male moslem. That's a lot of houris and a really interesting mix. Ah, science, how dim and colorless you are by comparison!
Newbeak
not rated yet May 29, 2011
Quote: "There are at least 9 different types of angels described in the Bible, ranging in appears to identical to a man such that a human observer can't even tell the difference until they were told so, up to more exotic creatures."

And don't forget the 72 houris for each male moslem. That's a lot of houris and a really interesting mix. Ah, science, how dim and colorless you are by comparison!

Nah,I subscribe to this quote: "Truth is stranger than fiction"..
Sinister1811
1 / 5 (4) May 30, 2011
What's strange is that there aren't many of these systems, in which, resemble our solar system. What this shows is a vast amount of diversity in planetary systems. I wish we could only see these planets for ourselves. They might be home to some really exotic life forms.
antialias_physorg
not rated yet May 30, 2011
And don't forget the 72 houris for each male moslem.

But you're there for eternity.
Even having 72 women can get boring after the first million years or so....
Newbeak
not rated yet May 30, 2011
And don't forget the 72 houris for each male moslem.

But you're there for eternity.
Even having 72 women can get boring after the first million years or so....

Not to mention a million years of nagging..
CSharpner
5 / 5 (1) Jun 06, 2011
Kev,
Except that life as we know it has the distinct appearance of not being a randomly occurring event, but rather a specific, planned and highly organised affair

Stop it. Just stop. How many times does it have to be explained to you that evolution is not random. Mutations are random, but there's an environmental filter. Mutations that don't work won't reproduce. Duh. We're all the descendants of those who survived. Double-duh. For 2 or more mutations that "worked", the ones that worked BETTER during rough times (drought, famine, extreme heat, extreme cold, and your favorite... flood) collected the minimal resources to survive. We are the descendants of those that won. Triple-duh.

If the universe is only 6000 years old, why is it that we can see objects that are more than 6000 light years away? How many times have you ignored this question?
Newbeak
not rated yet Jun 06, 2011
Kev,
Except that life as we know it has the distinct appearance of not being a randomly occurring event, but rather a specific, planned and highly organised affair

Stop it. Just stop. How many times does it have to be explained to you that evolution is not random. Mutations are random, but there's an environmental filter. Mutations that don't work won't reproduce. Duh. We're all the descendants of those who survived. Double-duh. For 2 or more mutations that "worked", the ones that worked BETTER during rough times (drought, famine, extreme heat, extreme cold, and your favorite... flood) collected the minimal resources to survive. We are the descendants of those that won. Triple-duh.

If the universe is only 6000 years old, why is it that we can see objects that are more than 6000 light years away? How many times have you ignored this question?

Don't bother segueing dude,they just drag you down to their level,and beat the shit out out you..
Newbeak
not rated yet Jun 06, 2011
Mitch,don't bother arguing with these dudes.They just drag you down to their level,and beat the shit out of you..
CSharpner
5 / 5 (1) Jun 07, 2011
Mitch,don't bother arguing with these dudes.They just drag you down to their level,and beat the shit out of you..

It's a bit of a game now and has a form of mild entertainment value. Also, we've discussed in the past whether it's better to ignore them or to respond and we, collectively, decided that we should respond for the benefit of those readers on the fence.

But yah, I get your point.
Newbeak
not rated yet Jun 07, 2011
Mitch,don't bother arguing with these dudes.They just drag you down to their level,and beat the shit out of you..

It's a bit of a game now and has a form of mild entertainment value. Also, we've discussed in the past whether it's better to ignore them or to respond and we, collectively, decided that we should respond for the benefit of those readers on the fence.

But yah, I get your point.

This site needs an "ignore user" button.Another website I frequent has this feature.
CSharpner
not rated yet Jun 07, 2011
This site needs an "ignore user" button.Another website I frequent has this feature.

You can try the filter function just above the comments section. Set it to 2 and you'll never see a creationists post again, unless you get there before anyonee's downvoted him, of course.
Newbeak
not rated yet Jun 07, 2011
This site needs an "ignore user" button.Another website I frequent has this feature.

You can try the filter function just above the comments section. Set it to 2 and you'll never see a creationists post again, unless you get there before anyonee's downvoted him, of course.

Okay,I have her set to "2".Hope that helps some..