Tag: Habitable zone

The Goldilocks Planet.

Neither too close nor too far from the Sun.

Towards the end of the lecture that Lord Martin Rees gave at  University of Melbourne’s Medical School in 2010, he spoke of the way that Planet Earth has warmed up these last 100 years, warmed up uniquely.  Why the word ‘uniquely’?  Because, for the first time in the ancient life of our planet, that warming is the result of the activity of a life species living on that planet; mankind.  It’s difficult to comprehend how special, how fragile and, therefore, how vulnerable is mankind’s ability to survive on Planet Earth.  That’s why a recent item on Martin Lack’s excellent blogsite Lack of Environment is published on Learning from Dogs with Martin’s kind permission.  But first let me quote a little from WikiPedia about the ‘goldilocks principle’,

In astronomy and astrobiology, the habitable zone is the region around a star where a planet with sufficient atmospheric pressure can maintain liquid water on its surface.[1]1 Since liquid water is essential for all known forms of life, planets in this zone are considered the most promising sites to host extraterrestrial life. The terms “ecosphere” and “Liquid Water Belt” were introduced by Hubertus Strughold and Harlow Shapley respectively in 1953.[2] Contemporary alternatives include “HZ”, “life zone”, and “Goldilocks Zone.”[3]

“Habitable zone” is sometimes used more generally to denote various regions that are considered favorable to life in some way. One prominent example is the Galactic habitable zone’ (the distance from the galactic centre). Such concepts areinferred from the empirical study of conditions favorable for life on Earth. If different kinds of habitable zones are considered, their intersection is the region considered most likely to contain life.

The location of planets and natural satellites (moons) within its parent’s star’s habitable zone (and a near circular orbit) is but one of many criteria for planetary habitability and it is theoretically possible for habitable planets to exist outside the habitable zone. The term “Goldilocks planet” is used for any planet that is located within the CHZ[4][5] although when used in the context of planetary habitability the term implies terrestrial planets with conditions roughly comparable to those of the Earth(i.e. an Earth analog). The name originates from the story of Goldilocks and the Three Bears, in which a little girl chooses from sets of three items, ignoring the ones that are too extreme (large or small, hot or cold, etc.), and settling on the one in the middle, which is “just right”. Likewise, a planet following this Goldilocks Principle is one that is neither too close nor too far from a star to rule out liquid water on its surface. While only about a dozen planets have been confirmed in the habitable zone, the Kepler spacecraft has identified a further 54 candidates and current estimates indicate that there are “at least 500 million” such planets in the Milky Way.[6]

So now to Martin Lack’s post.

Goodbye Goldilocks Planet?

Is it time to say goodbye to the Goldilocks Planet?

I hope not, because the next-nearest one yet discovered is 600 light years away! However, if we are indeed now passing a tipping point (i.e. as the widespread rapid thawing of Siberian permafrost suggests) both mitigation and adaptation will be almost impossible. Therefore, if we cannot reverse the damage already done (i.e. how can we make permafrost re-freeze or reverse the retreat of mountain glaciers?), we may have to accept that temperatures will eventually rise to a level at which the Antarctic first became glaciated 35 million years ago; and that sea levels will now rise continuously for several centuries – making any permanent settlement anywhere near the coast impossible (seeJames Hansen in Storms of my Grandchildren).

If your response to all this is to accuse me of being alarmist, all I can say is that I am afraid denial is definitely not a good evolutionary survival mechanism. Furthermore, as American high school science teacher – and now climate change activist – Greg Craven has said,“Unfortunately, the experiment is already running; and we are all in the test-tube!” I believe we must therefore hope that humanity will not repeat the folly of the former inhabitants of Easter Island; who chopped down all their trees for firewood and allowed all the decent soil to be washed away so they could not grow anything.

I think it is fair to say that 2011 was a difficult year for humanity and the planet; and 2012 could be worse. We now seem to be facing both a financial and an environmental crisis: Even at the tender age of 46, I can appreciate that the prospect of 6 years of austerity measures (here in the UK) is completely without precedent; worse even than the great depression of the 1920s. In the UK, public sector workers have been demanding a better pension! What about a better economic system, or even a better planet? If necessary, please forgive my impertinence but, how can people demand justice for themselves whilst ignoring all the injustices we are inflicting on those least able to adapt; and/or bequeathing to our descendants?

This is almost as pessimistic as my recent answer on ClimateSight to the question “Why are people who want to reduce – and possibly eliminate pollution – and create a safer world, considered obstructionist naysayers?“, which is… “If everyone lived as we do in ‘the West’, the planet’s ecological carrying capacity would only be about 3 billion [Paul and Anne Ehrlich (1996)]. Therefore we cannot solve poverty without allowing a lot of people to die or by wealthy people agreeing to moderate their over-consumption of the Earth’s resources. Sorry to be so blunt but, this is the simple answer to the question.” …Despite what detractors say this is not misanthropic eco-Socialism, it is reality. There is not enough decent farmland and/or resources of every kind for 7 billion people or more to live like we currently do in ‘the West’. If we are not going to deny the legitimate aspirations of poorer peoples to attain a better standard of living, we will have to moderate our over-consumption and/or pollution of the Earth’s resources. We cannot have it both ways.

Conclusion
If we continue to burn all the Earth’s fossil fuels – just because they are there and because we can – we will most certainly have to say good bye to our Goldilocks Planet. However, now that we know that what we are doing is causing the problem, would it not be a good idea to stop doing it? You know: When in a hole, stop digging, etc… As the Good Book says, “As a dog returns to its vomit, so a fool repeats his folly” (Proverbs 26:11).

Suggested New Year’s Resolution:
If we want things to change, I believe we must acknowledge that Clive Hamilton is right: climate change is a failure of modern politics – representative democracy is not working! Therefore, we must all take a much more active role in the process of government – this is called participatory democracy – and we must start by demanding that our politicians dismantle (or at least stop being misled by) the fossil fuel lobby who do not want their business as usual programme interrupted.

Having said all that, I would still like to sincerely wish you all the best for 2012 (although I hope the Mayan Calendar is wrong).

Kepler 22b

In a sense the discovery of a potential life-supporting planet isn’t news.

What do I mean by that sub-heading?

Many (and I mean ‘many’) years ago I was a student at Faraday House Electrical Engineering College in Southampton Row, London.  The College was closely associated with London University and one year there was an invite to attend a lecture by the famous British astronomer, Sir Bernard Lovell.

Sir Bernard Lovell and the Jodrell Bank radio telescope

Despite that lecture being about 45 years ago, I still recall Sir Bernard explaining the statistics of the universe to demonstrate that the odds of another planet somewhere ‘out there’ that could support life were huge.  (Just as an aside do read this interesting story of Jodrell Bank picking up signals from the Russian Lunar 15 just as Neil Armstrong and Buzz Aldrin prepared to leave the moon’s surface.)

So with the positive identification of this planet some 600 light-years away, Sir Bernard’s speculation has been proved spot-on.

But in another very real sense, the discovery of Kepler 22b is astounding.  Step outside the science of the find and just cogitate a little about the implications; the deep philosophical issues that Kepler 22b raises.  Here’s an extract from Northern Voices Online news,

The excitingly named Kepler 22b, a planet believed to have been discovered orbiting a star a mere 600 light years away, is being hailed as a “New Earth”. But sci-fi fans shouldn’t get too excited just yet: as always with these stories, the likelihood is that we have not met the neighbours. Or, if we have, they probably aren’t very exciting conversationalists.

Talking about the likelihood of intelligent life on Kepler 22b, Dr Lewis Dartnell, of the Centre for Planetary Sciences at UCL, said, “There are big hurdles that life has to get over, and we don’t know how big a hurdle the origin of life itself is. You simply can’t tell with a single datum – you can’t do stats when N=1.

The N that Dr Dartnell mentioned was earth: the only known planet inhabiting intelligent life forms, or better still, life forms of any kind.

Dr Dartnell further adds, “The interesting thing will be when we go to Mars and Europa and see whether there are bacteria there. It would be enormously significant if life is found there. But the next step, once Kepler has looked at a lot of planets, will be to see what their atmospheres are made of, using infrared spectroscopy.

“If one or two of them have oxygen in the atmosphere, it may be a transient thing – like Venus, undergoing a runaway greenhouse effect – but if we find, say, 20 Earth-like planets, all with the signature of oxygen in their atmosphere, then that would be very unlikely. Life would be the more reasonable explanation,” concluded Dr Dartnell.

Read the rest of this article here.

There are many news reports online but this short video caught my eye.

The latest NASA report is here from which is quoted,

NASA’s Kepler Mission Confirms Its First Planet in Habitable Zone of Sun-like Star

NASA’s Kepler mission has confirmed its first planet in the “habitable zone,” the region where liquid water could exist on a planet’s surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.

The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.

“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. “Kepler’s results continue to demonstrate the importance of NASA’s science missions, which aim to answer some of the biggest questions about our place in the universe.”

So let me leave you with this tantalising thought.  One day it will be confirmed that there is intelligent life on a planet out there in the universe.  That is likely to be one of the astounding events ever in the history of man on this planet.  Even trying some wild guesses about how that will change mankind’s self-perception is more than difficult – yet it will change the way we look at ourselves irrevocably!

I pray that I am still alive when that happens, as I’m sure many others must do.