Jackpot: astronomers tag Goldilocks planet While the Kepler mission turns up its ever-growing crop of exoplanets, a group of astronomers has announced an exciting find closer to home: looking towards Scorpius, there’s a super-Earth-sized planet just 22 light-years distant, with a habitable-zone orbit. Planets with the right orbit offer the best chance of harbouring …
We can begin to guess how many stars there are in our galaxy. We can begin to guess how many galaxies there are in the universe. The numbers are just huge. Incomprehensibly huge. Science is now starting to find planets on many stars. As science progresses I suspect it will become rarer to find stars without planets.
Given all of that doesn't it seem like arrogance of the highest order to suggest that ours is the only one with life, and that it was put here by some omnipotent power who chose our piddly little insignificant planet out of all those available?
to assume that we are not alone (I hope we're not btw), as we still don't know how (and thus how likely it is) life starts. The universe is very big, but very big and infinite are NOT the same thing.
Besides, as the late Carl Sagan pointed out, somebody has to be first. It could be us.
I expect to get lots of downvotes from those who believe we're not alone simply because they want to believe it. They're very similar to God-botherers in that respect.
We know that complex organics form readily; look at Titan and Enceladus for that. We also know that in an aqueous environment featuring complex organics and energy input that more complex molecules tend to form. We also know that the first Archaea appeared when the Earth had barely cooled; based on that single data point we can state with reasonable odds that the simplest chemistry of life happening in the lifetime of a planet is not a trillions-and-trillions against chance.
And given that last estimation, and the increasing odds that there are trillions and trillions of planets, we can conclude with decent odds there is, at least, simple life somewhere else.
That of course tells us nothing about the existence of advanced sentient species; we may well be the first of those to exist, at least within our light-cone.
Ah! Fermi's paradox and the Drake equation,
Fermi's paradox: If there are so many intelligent communicating civilisations in the galaxy where are they and why haven't they made contact?
Drake’s equation: The number intelligent communicating civilisations in the galaxy. Depending on the assumptions you make, some where between 20,000 and 'less that 1'.
"We can begin to guess how many stars there are in our galaxy."
It's a bit more than a guess, the galaxy is 100,000 - 120,000 light-years in diameter, about 1000 light years 'thick' and contains 200 - 400 billion stars.
"We can begin to guess how many galaxies there are in the universe".
Probably not relevant given the distances involved, The andromeda galaxy is approx 2.7 million light-years from earth, and is approaching us at about 120 kilometres per second[1] and will collide with our galaxy in about 4.5 billion years time.
"The numbers are just huge. Incomprehensibly huge".
"Given all of that doesn't it seem like arrogance of the highest order to suggest that ours is the only one with life"
No. If you take the optimistic figure of 20,000 civilizations in the galaxy then the nearest one is about 350 light years away .
[1] 721,546,273.66 furlongs per fortnight
Theists and atheists agree that there is an omnipotent power that caused our origin and controls our destiny. The former call this "God" or other semi-equivalent terms of varying (and sometimes ambiguous) plurality, and the latter diverge in the nature of their arguments but prefer describing this as causality, gravity, physics, chaos theory, repetitive randomness creating all possibilities, free will, and P!=NP.
As sects of theists bicker about their origin myths and the nature and name of the higher power, so do atheist sects bicker about their origin theories and the name and nature of our causation.
I suppose the difference is that the former irrationally ascribe to this power a motivation that relates specifically to Men. The latter irrationally deny motivation without evidence for such denial of willful causation - which is equally a matter of unproven Faith.
It has become unacceptable to say "I don't know." That's a shame because acknowledgement of your ignorance is a prerequisite to learning. There are many things to learn yet that we must let go of this dichotomy to know. Some of these paths may actually lead to a proof or disproof of Motive, of measuring and understanding the nature of the Motive if it exists. But we have to get past this fight to discover that.
Maybe this is a test of our Faith, or of our Reason, or our ability to Hope without reason. Possibly all three, as the Universe has many dimensions.
Having now offended every single person who might read this I can only hope to achieve the most thumbs-down of any Theregister comment ever. I suppose that would be an achievement of sorts. Is there a badge for that?
Gravity is proportional to mass, which at a fixed density goes as volume. Volume goes as the cube of the radius. Gravity is inversely proportional to the square of the distance from the center of the planet. So combining terms, gravity goes up linearly with radius, or as the cube root of mass.
In the case of a planet with 4.5 times the Earth's mass and the same density, then the surface gravity would be (4.5)^(1/3) = 1.65 times ours. Since the parent star is "metal poor" (astronomers call anything above Helium on the periodic table a metal), this planet is likely to have less iron core and heavy rock mantle, and more lightweight elements, We will have to wait for better telescopes to be sure what it's made of.
"O, Be A Fine Girl Kiss Me Right Now Sweety"
for a stellar evolution exam.
Mine is the one with the sky atlas in the pocket.
In the context of stars, a "dwarf" is a general term covering all sorts of small stars, whether brown (not big enough to actually even be a star), red (significantly smaller than our own, mostly red, and never going to the red-giant phase), yellow (similar to our own Sun), orange (smaller, more orange-looking), white (post-red-giant super-hot cinder, basically), or black (white dwarf that's cooled far enough to not emit meaningful amounts of light).
So we orbit a yellow dwarf, and this planet they've just found orbits an M-class (i.e. red) dwarf.
Black dwarf stars are a largely theoretical concept, as the universe isn't old enough for a white dwarf to have cooled enough to become a black dwarf.
Also theoretical are blue dwarfs which should be the later stages of red dwarfs but since red dwarfs burn so slowly no star has got anywhere near the blue dwarf stage.
Great isn't it :)
Also, I have a nagging feeling that planets in the liquid water area around red dwarfs would have significant problems for some reason (probably related to the proximity to the star), but I can't remember what it was. Shall I be arsed to Google or shall I wait for one of our boffin-minded commentors to fill in my blanks?
What is it about water that gets scientists saying that we can only have life when we have water available. I know it seems quite a useful substance but has anyone considered that we could possibly have life without water?
Maybe I am being stupid so I am heading behind a mask of ignorance.
Not a stupid question.
But how you search for other types of life forms when you got nothing to compare it so, no signatures to compare.
Looking for life out their that resemble the life on Earth is easier with today's technology than looking life with an unknown signature.
It fairly easy for scientist to detect water and methane for example.
Feel free to challenge some of the assumptions in what follows, but I think you'll find that they are all quite reasonable.
Life needs cells, both to get started in the first place and to specialize and compartmentalise functions in higher life-forms. It's hard to imagine anything complex enough to feed and reproduce that isn't organised out of some basic building block like a cell.
Cells need to be basically a drop of liquid enclosed in a membrane. It needs to be liquid to allow the flow of nutrients to and from interesting things like macromolecules. (It also needs to be a fairly good solvent for that purpose.) It needs to be enclosed to allow concentrations of those things to grow to interesting levels and concentrations of waste products to be expelled and kept out.
That liquid will be needed in large quantities. If it requires rare elements or complicated chemistry to produce it, it won't ever be present in large enough quantities to kick-start evolution.
Life also needs the right temperature range, which is one that is never so cold as to stop the interesting chemistry and never so hot as to destroy the delicate structures. This requires a balance between the available thermal energy and the typical energy of chemical bonds, both of which are determined by basic physics. The range may be fairly broad, but it is going to be the same range across the whole universe.
So a pre-requisite of "life as we know it" is a cheap material that is liquid at the right temperature. Water is probably the only substance known that fits the bill. Also, most molecules as simple as water are gases at room temperature. Water is only liquid at room temperature because of a happy accident of hydrogen bonding, so it is quite probable that it is the *only* suitable substance.
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So a pre-requisite of "life as we know it" is a cheap material that is liquid at the right temperature. Water is probably the only substance known that fits the bill.
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What about pressure? On a large mass planet with a thick atmosphere might you not, within a temperature scope that could support cellular organisms, have a different range of liquid chemicals? And bacteria can survive in some pretty harsh environments - including high pressure, high temperature environments (around thermal vents in ocean trenches for instance).
Granted, it wouldn't even be a nice place to visit, let alone live, but wouldn't it be possible?
Water is a remarkable liquid. It's a solvent that dissolves all sorts of other chemicals. Effectively these are different varieties of water. Maybe there are other simple molecules with amazing properties of versatility which chemistry could be based on. Hydrocarbons for instance, but these are thought to have been created by life rather than chemistry. They are used as signs of life.
I think the conditions for life are far more narrow. It would not surprise me if this was the only planet were conditions were just right. To recreate our conditions by chance would involve the combination of so many variables as to the universe not being big enough to hold them all.
For instance if there were 100 variables that all had to be within 1% for life to kick off then that would be a chance of 1 in 10^200
However if it was that easy then they would have made life in the lab by now.
How hard is it to make an iPad? Probably need better than 1% tolerances on more than 100 things. You don't make one of those by chance.
We have a planet, likely to be as warm as Earth, in the right zone for water and whatnot. Not much light though... so I'd guess that a nice intelligent efficient species would evolve, with big dark eyes, and a skin tone suited to absorbing infra-red. Sounds just like every alien in every movie up to about the year 2000.
Also - as a vegetarian I feel I must ask - how long do you think it will be before people decide that those supergiant shrimp they found should be fished for food?
But that's at 0.25c; whereas the fastest vehicle ever made by humans was probably the Galileo probe that entered the atmosphere of (crashed into) Jupiter at about 106,900 mph. At that speed (0.00016c) it would take 137,500 years to reach GJ 667C.
Remember what the HHGTTG says: "Space," it says, "is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..."
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