It is not clear to me why “Earth 2.0” as it is being called merits a decimal point unless someone is trying to imply that it lies somewhere between “Earth 1.95” and “Earth 2.05”, and I am even more puzzled to know what “Earth 2.1” might look like, but let’s pass over that without further comment.
Kepler 452b as it is more technically known has excited a lot of interest and speculation in the media since it was announced by NASA recently. I was particularly struck by the assertion that the planet lies in “The Goldilocks Belt”, viz. a region in the vicinity of a star that is neither too hot nor too cold to support the ingredients of life. Other commentators have observed that this is not sufficient: as far as we are able to judge, to support life a planet also needs to be part of a system of planets with at least one Jupiter-like giant to suck up all the debris that would otherwise rain down on the planet and cause repeated devastation. But I remember reading long ago that in practice most planetary systems will have giants among them because otherwise there is nothing to absorb the angular momentum of the gas clouds from which the planets condense. But if we can see “Earth 2.0”, why can’t we see “Jupiter 2.0” as well?
Even today The Times discusses how we might or should best communicate with possible alien life in an article and a leader. English is clearly a non-starter, but mathematics or the spectral lines of universal elements might be plausible candidates. But this still assumes a similar intelligence based upon similar cognitive structures and objectives, and whilst one supposes that the decimal version of pi as a mathematical constant must be universal, the inclination to know or use such a constant may not be.
As an aside, we are told that Kepler 452b is five times as massive as the earth, and many of us might therefore assume that it is also much bigger, even five times as big, but these things commonly and typically defy our intuition. Assuming Earth 2.0 has approximately the same density as Earth 1.0, how much larger does its radius need to be if its volume is to be five times as great? The answer is 1.71 times as large because 1.71 cubed is about 5. But Earth 2.0 would also have greater gravity and so it is likely that its inhabitants, if any, would have evolved differently in mass and shape to adjust for that difference.
Sceptics about life on other worlds have often said – I think this may be due to Dyson – things like “If they were there, they would be here”, but leaving aside the reply that “they already are”, the best response is “We are here, but we are not there”. However, turning our attention to these earth-like planets as potential homes for other life-forms is not without its dangers.
Should we, for example, be broadcasting our existence here to the universe without knowing who might be picking up the signal? Would embattled nations readily allow their citizens to tell all their secrets to a potential enemy without let or hindrance? Yet this is just what the SETI project is proposing: to turn its attention to seeing whether any intelligent communication is possible with Earth 2.0 and its putative inhabitants.
I was reminded of this only the other day during a dinner-table debate about AI and whether it is like anything to be a chicken. A friend was observing that as far as he is concerned it is not like anything to be a chicken, that chickens feel no pain and are incapable of pain, and that the notion of pain as something nasty requires the presence of higher-order cognitive abilities that render the notion of pain incommensurable with lower forms of life than humans.
I completely disagree with this, but my purpose here is to pose a different question. If we regard chickens (or even conceivably apes) as lower forms of life that we are entitled to experiment upon, cage and generally treat with indifference and disdain, not to say cruelty, on what basis would be argue (other than pure self-interest) that alien life-forms of a higher order of intelligence than ourselves should treat the human species with any greater respect? Specifically, while we are busily and keenly telling the universe that we are here on our defenceless lump of contaminated rock, why would we be doing more than advertising the presence of a free lunch? Or free subjects for interesting Mengele-like experiments? (“Free” here is of course ironic since the cost of the inter-stellar travel necessary to harvest the free lunch would almost certainly massively exceed the value of the crop, a point that seems completely to have eluded the misguided makers of the utterly dreadful Jupiter Ascending.) And the argument that says that we are obviously higher forms of intelligent life than apes is quite obviously completely bogus since we (some of us at least) do not believe that apes, dogs, rats and chickens feel pain or have any rights at all.
So if it should turn out that Earth 2.0 or Earth 42.0 (sic), being several billion years older than Earth 1.0, has already evolved to the extent that it has mastered inter-stellar travel and is on the lookout for new sources of minerals, lab rats and a free lunch, don’t say I didn’t warn you.