Three Planets in Habitable Zone of Nearby Star | Hacker News Reader

Three Planets in Habitable Zone of Nearby Star

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133 pointsLibertatea101 comments

This is an amazing discovery! The star is only 22 lightyears away, and it's got three potentially habitable planets. That's astounding. This is probably going to be one of our first destinations, when humanity starts building interstellar craft. Of course, the discoveries are still very early right now and we'll probably find all sorts of Earth-like planets quite close. But three Super Earths in the habitable zone of a close-by star? That's almost as good as it gets.

Edit: And surely this will be a focus of searching for life as well. A high concentration of life-capable planets in the same radio direction? Yes please. Also, I've often wondered if having a high density of habitable planets in the same system as your species would increase the chances and speed to becoming a spacefaring species. If you have a lot of places to go that are quite inviting and not that difficult to get to, you'll probably go.

Seems unlikely to be the first choice of destination on that basis. By the time the technology exists to reliably transport people (or equivalent amounts of mass) to other planetary systems in a usefully short amount of time, then the technology will also exist to cost-effectively (a) make everything habitable for baseline humans via habitats and other forms of engineering, and (b) engineer sentient entities that can live comfortably in native conditions near anywhere in a star system.

So whether or not the system has habitable zone planets will be irrelevant. Our descendants will go to the closest one first.

But it depends what is cheaper...

I think you're underestimating the importance of not living in bubbles for a) and opening a can of worms by assuming b).

and what would that can of worms be? :) ...really, if there is a "can of worms" to open here, we'll open it quite soon, well before any such voyage, by starting to do cosmetic-human-genetic-engineering, economic-oriented-human-genetic-engineering and warfare-oriented-human-genetic-engineering, and I'm pessimistic enough to bet on the third one as the first to crop up (nothing better than: "supper smart military engineers", "super smart, fit, sociopathic and fanatic - ie. unbreakable - spies" or any other such combos that I'm sure make up some twisted folks' wet dreams...).

Could still be useful in case anything ever happens to our solar system.

But 22 lightyears means it's still going to be one-way trip, even with matter/anti-matter engines. Unless we develop immortality by then of course...

Or procreating on the space ship.

How is that not a one way trip?

Staying on Earth is also a one way trip then.

I think the point was more about a one-way trip for a single person.

I'd agree that it's not a one-way trip for humanity, though. Once some of us get there (e.g., progeny of the original crew), eventually some of us could get back to Earth too (at some later date). Assuming Earth isn't destroyed by that point...

Probably by the time the progeny get back to Earth the current species will have self-annihilated and the earth would have returned to a more peaceful place, the atmosphere recovered, the vegetation replacing the asphalt and the oceans clean and pure. A few thousands years peace is exactly what the Earth needs.

Without the "trip" part.

It's not even a one-way trip unless you count procreation. It's likely a part-of-the-way-then-die trip.

Presumably any initial ventures that far afield would have a fairly small and very select set of passengers. People who are particularly intelligent or otherwise gifted. Or, indeed, multi-talented.

What if there offspring just aren't that bright? How can you ensure the mission succeeds over the course of several(/many?) generations?

Religion.

http://en.wikipedia.org/wiki/Orphans_of_the_Sky

We still don't know if we have to travel 22 light years to reach a point 22 light years from here.

Predicting what is impossible based on existing knowledge hasn't worked too well in the past.

Very roughly, if you had a ship capable of accelerating at 1 g (I know of no way to do this), you'd experience a decade of ship time to cross that distance.

http://www.daviddarling.info/encyclopedia/O/one-g_spacecraft... has other examples. They are round-trip, not one way, hence my describing my math as very rough.

Somewhat related; if you accelerate at a constant 9G it would take around 3 months to reach the speed of light.

That would be a pretty miserable 3 months. Can humans stay conscious for long at 9G?

Top Gun pilots can withstand 9G for quite a few seconds without a G-suit IIRC from documentaries on the topic.

Habitable zone planets are interesting primarily because there might be alien life on them, and only secondarily because we might want to colonize them. Our descendants will probably not allocate billions of dollars on a mission to a ball of dry rock when the alternative is a planet with a potential for life.

>Our descendants will probably not allocate billions of dollars on a mission to a ball of dry rock

if our descendants will still be thinking in billions of dollars ...

Same goes why goto the moon when we are not colonizing the sea. We will go there simply to proof our technology advancement.

22 lightyears is close enough for a conversation, although it would be quite the remote working challenge.

Probably more effective than the remote working conversations I'm having these days.

although it doesnt state their mass, as super earths it isnt likely to be much fun living there - higher gravity means people born in lower gravity systems would initially be oppressively heavy, and then just really really uncomfortable should they stay long enough to adapt; whilst the gravity well means getting off again is going to require much larger rockets (assuming similar atmospheric density).

Although if we can solve getting there we can probably solve constructing a space elevator to get on and off relatively fuel-free

As I have aged I have evolved a fairly effective simulation of a higher gravity environment. Running and falling down arent so much fun, but you can cope fairly well.

"That's astounding. This is probably going to be one of our first destinations, when humanity starts building interstellar craft."

Not going to happen for practical physical and economic reasons.

I'd sooner bet on a mass extinction event or singularity than a bunch of greedy superstitious primates actually develop interstellar travel.

OK, you need to watch some more Star Trek and get some optimism going ;)

I watched the last two ST movies and it just makes me want to see shit explode.

Everyone knows Star Trek films are terrible. :)

After 4 decades of reading/watching sci-fi, I've evolved to reality based entertainment. :p

Actually if you read John Barne's article on world-building,"How to Build a Future," where he talks about building the universe for the "Thousand Cultures" series, he discusses in detail the issues with local interstellar travel. (Since he has to plot around them.)

Also Star Trek is space opera, you probably should be reading hard sci-fi.

Hard scify is limited because is based on current knowledge. In 200 years thinks may have evolved quite a bit though. Maybe not to startrek standars, but something completely different that we can not imagine now(or that we can imagine but not give a theorem about).

Give those monkeys some respect please. Name any other species that have gone from walking around to flying in less than 100 years; gone from just barely flying to flying to the moon, walking there and flying home in 70 years; have completely eradicated a disease that killed millions of their numbers over the years (Smallpox); doubled its average lifespan; domesticated a competitive apex predator (Canus Lupes); build up a planet-wide network of invisible signals of lights such that a message can be send from one place on earth to the other in less time than it takes to say it out loud; build a bomb that can level a city - and used them as a basis for creating peace.

Yeah, we are not perfect, why would we be? We were the monkeys that were thrown out of the trees, that were forced out of Africa and into the icy Siberia and semi-cold Europe, we were the sure bet to lose and yet not only did we survive, we flourished.

> greedy superstitious primates

Press Release: Scientists found $VALUABLE_RESOURCE, making whoever gets there first the richest of all mankind, on $DISTANT_PLANET. Clearly, as God chose $OUR_PEOPLE, we must go there as soon as possible to fulfil his destiny.

(Now we just need to create some vast conspiracy to efficiently spread the message.)

Greed and superstition colonised America, Africa and Asia, lets people drive submarines to place their flag under the north pole and effectively made the human race the only race of remotely intelligent beings to live on all six continents.

Just remember being in a "habitable zone" is but one, small necessary (and by itself absolutely insufficient) condition for actually being "habitable" or sustaining life.

Recall that the earth is gifted with an active planetary core inducing a strong magnetic shield around the planet, has a single moon of sufficient mass and distance to throttle earth's rotation back to just the right speed to have a stable atmosphere, as well as the proper chemical composition...

That's what I was thinking. Isn't Mars in a habitable zone as well?

It's in the border. In theory can be terraformed.

Looks like it depends how you define "habitable zone" - it seems that if you are conservative about it (i.e. Earth sized planets remaining habitable) then Mars is actually outside of that zone:

http://en.wikipedia.org/wiki/Circumstellar_habitable_zone

I see don't see where that article suggests that Mars is outside the habitable zone by any reasonable estimate. The only part I see questioning Mars's position suggests that Mars might actually not be as close to the edge as we think. Mars's lack of habitability is partly because of its position, but also partly due to other factors like its lack of a magnetic field and atmosphere. If you somehow "poofed" a copy of Earth into Mars's place, I think it would be considered habitable (but still not really for humans), though I'm not really qualified to say that with any certainty.

In the diagram in that article the dark green band is the conservative habitable zone - the orbit of Mars looks to be pretty much completely outside of that area.

Venus is right on the edge too. We don't have to be wrong by much for it to be habitable, in theory. One can imagine a world covered in clouds, but with a habitable surface, or some set of geological structures that go high enough to be cool enough to live on. Earth life might not like it there, but we've got extremophiles already here on Earth living in similar conditions.

Mars and Venus provide instructive examples on why being in the zone is merely one small prerequisite. We talk about it because it's just about the only characteristic of these planets we can see, not because it's the only important characteristic. Mars has too little atmosphere, among other problems, and Venus has way the hell (word chosen advisedly) too much.

we built this (cloud) city on rock and roooollll!

I didn't understand your comment until I glanced at the wikipedia article for the atmosphere of Venus[1]. With a surface air pressure of 92x and carbon dioxide making 96.5% of the atmosphere, the surface of Venus is a no-go even before considering the extreme winds.

>The atmosphere of Venus is much denser and hotter than that of Earth. [...] The main atmospheric gases are carbon dioxide and nitrogen. Other chemical compounds are present only in trace amounts.

>Despite the harsh conditions on the surface, the atmospheric pressure and temperature at about 50 km to 65 km above the surface of the planet is nearly the same as that of the Earth, making its upper atmosphere the most Earth-like area in the Solar System, even more so than the surface of Mars. Due to the similarity in pressure and temperature and the fact that breathable air (21% oxygen, 78% nitrogen) is a lifting gas on Venus in the same way that helium is a lifting gas on Earth, the upper atmosphere has been proposed as a location for both exploration and colonization.

[1]: https://en.wikipedia.org/wiki/Atmosphere_of_Venus

No; no liquid water at the surface.

http://www.astro.sunysb.edu/fwalter/AST101/habzone.html http://en.wikipedia.org/wiki/Circumstellar_habitable_zone

EDIT: to be more precise, the conditions aren't right for there to be liquid water at the surface.

So our sun has three rocky planets near the habitable zone. One of them evolved intelligent, space-travelling, radio-communicating species. The other two have robots on them. If we're using our own system as a kind of model for projecting ideas about Gliese 667c, I'd be pretty optimistic about the chances.

Except you have no idea of the relative probability of these events. Two of them have robots on them precisely because of the space-travelling, radio-communicating species on the third. But we have no firm data on the likelihood of a random planet in a star's habitable zone being rocky, having an active core, and a slow enough rotation for a stable atmosphere. Nor for that matter the expected percentage of time that such a planet should be expected to be populated with intelligent life over the span of its existence.

You're effectively saying, "Somebody else has discovered a swan. The only swan I've seen is white. Therefore, I expect that this new swan is white as well."

If we're using our own system as a kind of model for projecting ideas about Gliese 667c, I'd be pretty optimistic about the chances.

The problem is that we cannot do that without succumbing to selection bias. We don't know how many things had to go just right to give rise to life, let alone a technological civilization, we just know that it has happened (at least) once in the whole universe.

http://en.wikipedia.org/wiki/Selection_bias https://en.wikipedia.org/wiki/Anthropic_principle

And on one of those two planets, all the robots are DEAD. If that isn't the setup for an awesome Doctor Who/Culture cross-over fanfic, I don't know what is.

> Just remember being in a "habitable zone" is but one, small necessary (and by itself absolutely insufficient) condition for actually being "habitable" or sustaining life.

It's not even a necessary condition. The 'habitable zone' is based on the possible presence of water on the surface of the planet, which it is argued makes it more likely life could have evolved. But, it isn't a requirement, at least as we understand it. For example, Europa, a moon of Jupiter, is well outside the habitable zone but is believed to have a sub surface water ocean that could be capable of spawning life.

We are outside the habitable zone :\

ref: http://www.newscientist.com/article/dn23118-earth-and-others...

I think mineral-rich asteroids would be a likelier first destination for interstellar colonists than an Earth-like planet. The Earth's gravity well is an enormous impediment to space travel. And in micro gravity, we can fly! A large enough asteroid with a hollowed out core with a stable star nearby to provide energy would be the kind of place I'd expect to see colonized first. Planetary scale terraforming can come later.

Having said that, this is an exciting discovery. Kudos to the team that discovered these planets.

> "And in micro gravity, we can fly"

And our bodies rapidly fail... Any colony for contemporary humans will need earth-like gravity, artificial or otherwise.

Well, contemporary humans are transforming into cyborgs.

In which case: who needs micro-gravity to fly?

One wonders about the ramifications of this.

Imagine how our history would be different if we had evolved on a planet with two other planets that could reasonably be expected to support people living on them. Or our experience as we visited those neighboring planets and interacted with stuff that possibly evolved there in ways that are different to the way we evolved. And with the possibility that we were the species that hadn't evolved quite as quickly such that one of the neighboring planets colonized us before we reached their level of technology.

Now imagine we notice that a star "near" us has similar conditions to those on the three planets in our system on which we have established our civilization.

Do we explore them or do they explore us? :-)

I've always thought that we are lucky to have the moon. A nice little stepping stone.

Link is broken (404). Here's an alternative:

http://www.sciencedaily.com/releases/2013/06/130625073544.ht...

Based on the artist's conception: we've discovered Tatooine!

It sounds like there's two problems for anyone/thing living on these planets. First, they're closer to their star than Mercury is to our sun. Unless the atmosphere is pretty dense and there's a strong magnetic field, the radiation on the surface is going to be pretty intense.

Second, one of the notes at the bottom of the article says the team believes the planets day and year are the same length, so one side always faces the star. That'll reduce the habitable area to a ring around the planet instead of the entire surface. We'd still be ok to put a colony there and we could probably generate lots of energy from the temperature differential, but it's much less likely that life would have evolved in that environment.

I'd like to see a simulation of how this system's orbits work. Amazing

When the Exoplanet Explorer app gets updated with this data we're going to be in for a treat. https://play.google.com/store/apps/details?id=org.burlock.ex...

For anyone who is interested in this, I highly recommend listening to the podcast of Richard Pogge's Astronomy 141 course at Ohio State Uni.

http://www.astronomy.ohio-state.edu/~pogge/Ast141/#lectures (iTunes link: https://itunes.apple.com/us/course/id559775126 )

Here's the overview:

Astronomy 141, Life in the Universe, is an introduction to Astrobiology. The topics covered in this course lie at the interfaces between astronomy, chemistry, biology, geology, and the earth and planetary sciences. We will learn about scientists' ongoing quest for answers to some of the most fundamental human questions: How did life originate on Earth? Is there life on other worlds? Are we alone in the universe? What is the long-term future of life in the universe?

What would be the timeframe of reaching/colonizing these planets? With another 20 years of engine development, would it be possible to reach these planets in our lifetime? That would be a world-changing event.

Yes it would be possible. Project Orion in the 1950s demonstrated that using nuclear pulse propulsion, you could accelerate to (max) 0.1c for intersteller missions. If we were to actually spend a little bit of money and effort on real space travel - which we're about to, if SpaceX and Plantery Resources succeed - I think it's completely reasonable to think that we will launch (and perhaps arrive) on these planets in our lifetimes.

It's optimistic, sure, but it's possible.

0.1c would make this a 220 year journey each way. So what you're really saying is: no, it's not possible reach these planets in our lifetime.

I was imagining we would also be researching biology at the same time, and would be able to live that long or sleep during the trip. If we're able to move at .1c I can't imagine we'll still die as quickly as people born in 1900.

I saw a presentation on this at a DARPA meeting a couple years ago. It is exactly the kind of thing that could make long-term space travel possible.

http://www.wired.com/dangerroom/2007/12/zombie-mouse-ma/

There's a huge gap between "20 years from now, we won't die as quickly as people born in 1900" and "20 years from now, people will live four times as long as they do in 2013." The former is quite likely. The latter is pretty far out there.

Is that fast enough for relativistic effects on-board? It might be 220 years for those left behind, but for the people on the ship it might be less than a lifetime. They'd probably still have to raise children on the way to take care of the exploring when they got there.

218 years, instead of 220.

http://www.wolframalpha.com/input/?i=time+dilation+calculato...

There are no substantial relativistic effects at 0.1c; the time dilation factor is sqrt(c^2 - v^2), so about 0.995 in this case.

you have to take into account that the closer you get to light speed, the slower time goes. In other words, people on the space ship may age slower, meaning that 220 years may be a lot less to them. What is the equivalent of 1 earth year on a spaceship going at 0.1c, that is the question.

The relativistic correction is

Time_on_Ship = Time_on_Earth * (1 - (v/c)^2)^(1/2)

If v <<c we can use the Taylor approximation

Time_on_Ship =~ Time_on_Earth * (1 - (1/2) (v/c)^2)

Distributing

Time_on_Ship =~ Time_on_Earth - Time_on_Earth (1/2) (v/c)^2

With the current number, assuming instant acceleration to simplify the calculations:

Time_on_Earth = (22/.1)

Time difference =~ (22/.1) (1/2) * .1^2 years = 1.10 years

The important detail is that for small speeds, the correction is quadratic, so the difference is small unless the speed is very close to c. In this case the correction is only 0.5%.

Good stuff!

Thx Gus

The Lorentz factor doesn't really make an appreciable difference until you get much closer to c. For instance cutting the trip time in half would require .866c.

.99c would cut the trip down to ~30years.

> .99c would cut the trip down to ~30years.

Surely you forgot to take into account that increasing the speed shortens the trip as well as dilating time?

Travelling at 0.99c would take 22 years to reach that from an observer's point of view, which would be 3 years for the people on board

You're completely correct. I didn't take that into account. No more comments about relativity before coffee.

Why max to 0.1c? Is there friction in space or so?

Sort of... the faster you go, the more energy you need to accelerate even faster. The Orion design, IIRC, basically involves sitting on a big iron plate and tossing nuclear bombs under it. Each bomb can only impart a certain amount of energy and at some point you're not going to accelerate any faster unless you shed some mass.

You will shed some mass in the form of the bombs you're blowing up, and whatever you break off the bottom of the plate you're blowing them up against, and I think the design requires a front shield too which will also deteriorate over time and shed mass, but those all probably balance out around the 0.1c velocity.

Last I read up on such ideas, the better design was to use a sail in front of the ship to catch the push from each explosion, then you only need the one radiation shield. I think it also allows for making a larger surface to catch the explosive push, and it depends on materials absorbing loads through tension rather than through compression.

Part of the problem is that you need to decelerate at the end. Maybe it's possible to use a gravity assist to decelerate from 0.1c inside the destination solar system, but otherwise you need to turn around and thrust the other way at about the half-way point.

Another part of the problem is the faster you want to go, the more fuel you need, which makes your ship more massive.

Use a mag-sail as a "brake" to slow down at the destination star.

BTW How do we know that interstellar space is empty, that there is no dust, stones, etc.

Probably even very small objects make high-speed flights impossible because of collisions.

I believe we know that it's not empty. Take the asteroid belt: there are millions of objects there, yet we fly through it with interplanetary probes, no problem.

We know that space is not empty, but it's empty enough.

I've heard our asteroid belt described like this:

The odds of randomly happening on an asteroid while traveling though the asteroid belt is about the same as randomly happening on a ship in the Pacific Ocean.

So.... interstellar colonisation kickstarter project anyone?

We define the word habitable to be the ability for a planet to have life on it. But that is by standards of Oxygen/Nitrogen breathing, H20 drinking lifeforms. Who's to say that there aren't carbon life forms that have evolved to live off elements that are toxic to us

We have those life forms here already=) Microbes that eat arsenic. I am sure there are a lot more examples in extreme areas of our planet if there was a bigger budget to find them.

No one, but finding ETs is only half of the excitement. The other half is interstellar colonization.

22 light years, in layman's terms equals 5 billion round-trips from San Francisco to Paris.

- SF to Paris (1 trip = 5831.79 miles)

- double that for a round trip

- 22 light years = 5.87849981 × 10^12 miles

- Divide 22 light years by the round trip, yields total trip count.

Actually, it's WORSE.

1 light year = 9.454 x 10^15 meters 22 light years = 2.080 x 10^17 meters SF to Paris, round trip = 1.877 x 10^7 meters Number of trips = 1.108 x 10^10

In layman's terms, it's about 11 billion trips!

Here's another way to get a sense of scale. The earth rotates the sun at an orbit with semi-major axis of about 150 million kilometers. Using some data you can determine that the orbit of Earth is about 9.398 x 10^11 meters in circumference. Divide the distance to the star by this number to get 2.213 x 10^5 years. That is, it takes the Earth about 220 thousand years to go this distance around the sun.

I'm getting a 404 error. Even the link posted on their homepage sends the same error.

It should be easy to detect whether any radio signals come from that direction.

1.29326996 × 10 to the 14th miles = Nearby

Some exoplanets discovered recently are 10,000 lightyears away. So indeed, 22 lightyears is absolutely nearby.

Kittens are gigantic, compared to protozoa. That doesn't mean we should describe kittens as cute, fuzzy, and gigantic. I would be ok with "only 22 lightyears away." But "nearby"? Most people have a hard time grasping the size of our galaxy. "Nearby" does not help promote a good understanding of the discovery IMHO.

I think it promotes understanding of the discovery, as well as future discoveries, actually. Those who don't know that our galaxy spans hundreds of thousands of lightyears may not have a conception at all for how far away, and comparatively, how close, some objects are. It's clear we're talking about planets around other stars, and this is almost as close as it gets, so calling it 'nearby' is a pretty excellent description I think.

Words like these are inherently relative and depend on context.

If the context is protozoa, then a kitten is absolutely "gigantic". There's nothing wrong with that at all.

The local grocery store is "nearby" for me, about 500 meters. I sit "far away from" the window in my office, even though it's still two orders of magnitude (and then some) closer than the store. Context.

"Nearby" is absolutely an appropriate word to use for a distance of 22 light years when discussing exoplanets.

especially when you consider that Alpha Centuri is 4.367 light years away, and that is the closest thing, 5 times that is pretty damn nearby.

If your friend lived 5 houses down the street I think that'd qualify as nearby.

The planets have three suns? Only three more suns to Nightfall!

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