The Habitable Zone

Few things are more exciting to me than the idea of finding a habitable planet somewhere out in space. Given the hundreds of now confirmed exoplanets, and the likely millions more that we have not yet found, it seems inevitable that we will find an exoplanet in the habitable zone. Part of figuring this out is understanding where the habitable zones will be.

Using the latest data, the Penn State Department of Geosciences team has developed an updated model for determining whether discovered planets fall within a habitable zone.

Aside from the obvious awesomeness of the fact that people are spending time and energy figuring this stuff out, I think that the most exciting part of all this is that we are likely to find a viable planet in the habitable zone of another star sometime in the next few years.

The graphic shows habitable zone distances around various types of stars. Some of the known extrasolar planets that are considered to be in the habitable zone of their stars are also shown. On this scale, Earth-Sun distance is one astronomical unit, which is roughly 150 million kilometers.

The graphic shows habitable zone distances around various types of stars. Some of the known extrasolar planets that are considered to be in the habitable zone of their stars are also shown. On this scale, Earth-Sun distance is one astronomical unit, which is roughly 150 million kilometers.

The big question will then be what to do about it. I hope that the next step will be to point some high-powered telescopes at it and see what else we can learn.

The science fiction loving part of me is very interested to know what will happen to our own cultural assumptions if, or when, we find such evidence. If you think the anti-science crowd gets offended at the idea of an old earth and the concept of evolution, what do you think they will do with evidence that we are not as special as we used to think we were.

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The Great Filter

We know now that our galaxy is filled with rocky planets, a percentage of which will almost certainly fall within the category of ‘earth-like’.  (100 billion stars mean even a 1:1000000 chance allows for 100 000 earth-like planets).  If we ever do find evidence of microscopic life on Mars the odds will go way up as well – meaning that life is much more likely to exist elsewhere.   And yet, we see no evidence of extraterrestrial life in our observations of the galaxy, a fact known as the ‘Great Silence’.

There could be many explanations for this phenomenon.  A short and not at all comprehensive list includes:

  1. We are leading the development curve.  Other life has not yet reached or surpassed our current development level, and those who have are so far away the evidence still has not arrived (1000 light years is really far away).  This theory makes the assumption that humans are outliers, which is always possible but statistically less likely.
  2. We are well behind the development curve, and would not recognize evidence of extraterrestrials because we haven’t developed far enough yet.  Just as an Amazon tribesman might not grasp the significance of a Predator drone at 20,000 feet, we might not recognize or understand what we are looking at.  For a long time we assumed that radio transmissions would be evidence of life, but would a 1970s SETI researcher have recognized a typical WiFi or cell phone transmission as evidence of sentience, or merely dismissed it as noise? Even if an ET civilization did have recognizable transmissions at some point, it wouldn’t have been obvious to anyone on Earth until the middle of the last century.  It is possible that ETs developed beyond us while we were bashing away at each other with clubs or muskets.  The thought that irrefutable evidence of ETs might have been readily available in the form of recognizable radio transmissions during the Spanish Inquisition makes me chuckle for some reason.
  3. Life is harder than we think.  Just because it happened here doesn’t mean that it is easy.  Perhaps the places where it might happen number in the dozens.  Add in some random elements like planet killing asteroids, and we have a quiet galaxy.
  4. The Great Filter.  The notion that some point in the development of a civilization is very hard to overcome, and that most species do not actually succeed.  If this filter is in the past, something like the development of language or writing, then we may be outliers leading the pack.  If it is in the future, like developing into a star-faring civilization before we destroy our own planet, then we might be in trouble.  We certainly aren’t doing well at planet management so far, it isn’t hard to imagine humans entering a downward spiral long before leaving the solar system.

Whatever the situation, our current rush of exoplanet discoveries and the dawn of private space travel make me hopeful that humans will be able to explore at least our own solar system, with an eye to exploring further in some capacity (biological or not).  Meanwhile we should really be trying to find ways to avert civilization killing catastrophes like war and climate collapse.


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Can we go to Alpha Centauri?

Alpha Centauri

This artist’s impression made available by the European Southern Observatory on Tuesday, shows a planet, right, orbiting the star Alpha Centauri B, center, a member of the triple star system that is the closest to Earth. Alpha Centauri A is at left. The Earth’s Sun is visible at upper right. Searching across the galaxy for interesting alien worlds, scientists made a surprising discovery: a planet remarkably similar to Earth in a solar system right next door. Other Earth-like planets have been found before, but this one is far closer than previous discoveries. Unfortunately, the planet is way too hot for life, and it’s still 25 trillion miles away. (AP/ESO, L. Calcada)

The recent confirmation of a planet circling our nearest stellar neighbour is nothing short of thrilling.  Sure, it isn’t habitable, circling Alpha Centauri B in something like 3.2 days, but the fact it exists at all is a major breakthrough.  If we can find a few more planets over there, we might seriously start thinking about actual space exploration.  Kudos to the European Southern Observatory team for making the discovery, and having the scientific self-discipline to spend three years confirming it before the announcement.

So, what are the realistic considerations of a potential interstellar mission?  In my opinion, the barriers are enough that we won’t be doing it for a very long time, if at all – barring some black swan scientific discovery like a warp drive or other FTL technology.  No doubt we have much to learn about physics and the universe, but we cannot assume that future scientific discoveries will help us indulge our urge to explore.


One of the biggest barrier to such travel is time.  If it takes 100 years to reach another star, nobody is going to want to go.  And if we might find nothing of worth and have to set off somewhere else, the incentive is too small to bother, especially assuming a significant cost in energy and resources to send a viable ship that far and for that long.

So, how can we address the time barrier?  Nobody wants to live our their lives (and the lives of the next 40 generations) in a spaceship – there haven’t been many human societies that have lasted anywhere near that long.  But what if a human lifespan was dramatically longer, even functionally immortal?  It seems unlikely now, but no more so than warp drives and wormholes.  In fact, we spend significantly more resources and energy studying health than we do on space.

A thousand-year old person, or a person who might live for 10,000 years, might be much more willing to undertake an interstellar voyage.  It is hard to know what humans would be like if they had lifespans on that scale, but I imagine patience would be much more common.  Some people would no doubt appreciate an opportunity to spend a few centuries working on something that interests them.  Maybe they could finally finish the Harry Potter novels, or read those impenetrable Tolkein books that aren’t LOTR.


The other big barrier to interstellar travel is cost.  Not in dollars but in resources and energy.  It will take a lot of energy to send even a tiny ship to another star, and a lot of resources to support even a tiny crew for thousands of years.  And the more resources needed, the more energy as well, a vicious cycle that could well make interstellar travel impossible.

However, there are some resources that weigh nothing, like technical and scientific knowledge.  Far better to send a few small machines capable of making anything on arrival as needed than to try to send everything in advance.  Similarly, it would be a lot easier to send some raw materials for the manufacture of humans on arrival (i.e. genetic material and the means to grow and educate people when they get there).  Trying to send actual grown humans might be impossible and absurdly expensive, but sending a tiny ship with all it need to build on arrival might actually be viable.

Of course, we don’t have the scientific knowledge to build a person from scratch right now, but we much closer than we are to an FTL drive (if such a thing is possible).  It may be that humans who arrive at another star will be born of that star, and any further exploration would be similarly done by their descendents.  Von Neumann Machines, but organic.

All of this is a long way off, barring the black swan event that changes everything.  (My personal favourite would be friendly contact from somewhere else once we reach a certain level of development).  Nonetheless, the discovery of planets in the neighbourhood makes me optimistic that someday, someone will go for a closer look.



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Search for Exomoons finds a Planet – Crowdfunded science

New Discovery Funded by Petridish Published in Science! | The Petridish Blog.

Remember the Petridish crowdfunded science site?  This blog donated a few dollars to the Search for Exomoons research awhile ago.  Well, they haven’t found an exomoon yet, but they did just publish a newly discovered planet in Science, a happy byproduct of the successfully crowdfunded research.

When the team looked at the data that Kepler has made public, they found something unusual with the planetary candidate KOI-872.01 (KOI stands for “Kepler Object of Interest”). It had some of the largest timing variations ever detected—about two-hour variations in an orbit that takes a bit under 34 days. But there was no sign of any transit duration variations, which should be present if there was a moon. All of which suggests that the planet was being pulled around by another planet Kepler hadn’t detected.


Hooray.  Though our contribution was relatively tiny, it feels really fantastic to have contributed at all.  Petridish has a number of exciting looking projects currently seeking funding, though I am personally holding out for another SF/space related idea.

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Space Exploration as Moody Video

I have no idea what NASA sees as the purpose of this video (fundraising?), but it pushes all my ‘like’ buttons so it seemed best to share it here.  That said, I don’t actually think that NASA will be leading the way, I think it will be competing and somewhat chaotic private interests.  Starting with some eccentric billionaires, but eventually becoming something else.

Youtube link is here

via Geekosystem.

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Your Last Chance to see Venus Transit the Sun

2004 Transit of Venus, courtesy of Wikipedia.

On June 6, 2012 Venus will transit the Sun.  Pacific Islanders will see it best, but most of the world will see part of it.

Transits of Venus occur only on the very rare occasions when Venus and Earth are in a line with the Sun. At other times Venus passes below or above the Sun because the two orbits are at a slight angle to each other. Transits occur in pairs separated by eight years, with the gap between pairs of transits alternating between 105.5 and 121.5 years — the last transit was in 2004.

In other words, the next transit will be in a month, and then you’ll have to wait 115 years to see it again.  I am optimistic about the scientific advancement of health and extension of life, but even an SF-soaked optimist like myself doesn’t seriously expect to live for another 115 years (not that I would mind).

Edmond Halley proposed using a transit of Venus to predict the precise distance between Earth and the Sun, known as the astronomical unit. As a result, hundreds of expeditions were sent all over the world to observe the 1761 and 1769 transits. A young James Cook took the Endeavour to the island of Tahiti, where he successfully observed the transit at a site that is still called Point Venus.

Hopefully most of us won’t manage to witness the transit of Venus and get killed by cannibals in the same lifetime, but if we take the time to look for it we will be walking in the footsteps of giants.  Modern astronomers will use the transits to refine theories about observed transits in other solar systems, furthering our understanding about what we see far into space.

Via Science Daily and Geekosystem.  Quotes from Science Daily.

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Off-Planet Resources

Esther Inglis-Arkell over at io9 has written a handy guide for where we’ll need to go to get resources once we escape the gravity well.

We are told two things constantly these days: 1) We should conserve our precious resources, and 2) we should devote more time and money to the space program. And let’s face it, these two goals are directly opposed to each other. Not just because the space program takes up resources, but because if we have a space program that’s sufficiently advanced, we shouldn’t need to conserve resources. We should be able to grab them from other worlds.

at io9

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First Exomoon Petridish project meets its target!

You may remember my post last week when I committed some funds to Petridish, a science crowdfunding site.  Well, they did it – the Search for the first Exomoon has now met its funding goal.

Thanks to anyone who contributed.  Yay science!  I will keep my eyes open for more projects that look interesting.  I encourage you to have a snoop through the projects that are currently seeking funding.  They all look great.


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Here’s what the weather on Mars would really look like

There is an interesting article about the weather on Mars over at io9. 

But if you really want to experience what Mars can come up with, Mariner Valley would be a great place to start. The monster 3000-mile-wide canyon (rift valley, if want to be pedantic) is so long that one end will be well into the night side of Mars while the other end is still in full sunlight. The temperature difference can cause terrific winds to barrel down the canyon…at velocities reaching the speed of sound on the planet.

Go read the rest over here.


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Red Dwarfs as a Potential Host for Habitable Planets

There is a new article over at The Daily Galaxy which discusses the possibility of habitable planets around red dwarf stars – which are abundant in our galaxy and others.

The researchers modeled how reflective ice and snow would be on simulated planets orbiting two real-life red dwarfs. Ice and snow are less reflective against longer, redder wavelengths, while red dwarfs obviously have fairly red light to begin with.

This means the outer edge of the habitable zone around red dwarfs might be 10 to 30 percent farther away from its parent zone than once suggested.

“I was surprised that the effect was as large as it was,” Joshi told Astrobiology Magazine. “The zone where liquid water is stable on a planet’s surface is farther away from such stars than previously thought.”

The science is fascinating.  As a science fiction fan I am most interested in what will happen when (okay fine, ‘if’) we have a discovery of a habitable planet.  Will it be suppressed?  We have to expect that the world’s religions will have a very hard time accepting such an event, if the ongoing hostility towards the theory of evolution is an example.  I suspect that whatever astronomers make the announcement will be quickly vilified by extremists of all stripes using the classic ‘if you can’t argue with evidence attack the messenger’ approach.

There is a well-worn SF trope of first contact, but I think something as simple as ‘first evidence’ would be an amazing event.  Given the state of our world today, I suspect such a discovery would also be catalytic in almost all areas of our societies, and would probably trigger a period of ‘interesting times.’  What would evidence of another habitable world do to mortgage rates or the stock exchange?  What about the next major election in almost every democracy?  What effect would it have on existing autocratic systems?


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