"The Universe is a pretty big place. If it's just us, seems like an awful waste of space."
Observable Universe contains 10x more galaxies than previously thought (2016)
141–150 of 161 posts
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#142Earlier quoted context omitted.
But it's fairly likely to be carbon-based, as carbon is the simplest existing element with the maximum amount of valence electrons. And generally, simpler (= lower ordinal number) means more stable, as well as more likely to arise (as less energy is required, e.g. in stars).
Do you think the periodic table contains all the elements in the universe?
Yes, since from what I understand, any heavier elements would be so unstable they wouldn't last a billionth of a second.
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#143And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even com…
> How, when given the evidence of practically infinite planets out there [...] can we even consider the possibility that this is the only planet with life? Human minds aren't good with very large numbers. What seems "practically infinite" to us - isn't, really. The number of all planets in the universe is said to be in the ballpark of 10^24. Meaning (obviously) if you keep on dividing it by 10, in just 24 steps you g…
That's an interesting argument. But do you have some of specific conditions that might qualify?
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#144And some people still aren’t sure if there is other life beyond Earth. :) That's entire galaxies. Not just stars, and that's just the observable universe. We are still being surprised by the lifeforms we observe here on Earth, and the environments and conditions they can thrive in (including the outer hulls of our spacecraft), and we still have yet to discover and catalog all the life on our planet. Life may even com…
> How, when given the evidence of practically infinite planets out there [...] can we even consider the possibility that this is the only planet with life? Human minds aren't good with very large numbers. What seems "practically infinite" to us - isn't, really. The number of all planets in the universe is said to be in the ballpark of 10^24. Meaning (obviously) if you keep on dividing it by 10, in just 24 steps you g…
I wonder how long much longer it will take for the astronomers to get the technology that would allow them to hunt for life in other stellar systems so that we can check all this out.
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#145Earlier quoted context omitted.
I agree with you in that we will probably never have contact with another sentient species of extra terrestrial origin. The distances are to vast, the lifetimes of civilisations and even species too short and so on. However I do think that you vastly underestimate the probability of life. Take a look at https://en.wikipedia.org/wiki/Earliest_known_life_forms . See how quickly life appeared once the earth had cooled d…
But it's fairly likely to be carbon-based, as carbon is the simplest existing element with the maximum amount of valence electrons. And generally, simpler (= lower ordinal number) means more stable, as well as more likely to arise (as less energy is required, e.g. in stars).
There are other theoretical biochemistry possibilities[1]. Silicon, for example, works well in low-pressure environments. It's an immense stretch of the imagination to think about life-forms that use semiconductors to do useful work, but is certainly a fun thought experiment.
[1]: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#146Earlier quoted context omitted.
I agree with you in that we will probably never have contact with another sentient species of extra terrestrial origin. The distances are to vast, the lifetimes of civilisations and even species too short and so on. However I do think that you vastly underestimate the probability of life. Take a look at https://en.wikipedia.org/wiki/Earliest_known_life_forms . See how quickly life appeared once the earth had cooled d…
See how quickly life appeared once the earth had cooled down? https://en.wikipedia.org/wiki/Panspermia I find this a compelling possibility.
Highly unlikely.
DNA's 'half-life' is about 500 years. Meaning that each nucleotide-bond has a 50% chance of breaking every 500 years.[0] At the time scales of interstellar travel, DNA based life is very unlikely to survive.
EDIT: This then means that DNA based life was likely a local phenomenon. This also means that other planets may have done the same and that a 'interstellar seed' is not required.
[0] https://www.the-scientist.com/?articles.view/articleNo/32799...
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#147Earlier quoted context omitted.
> How, when given the evidence of practically infinite planets out there [...] can we even consider the possibility that this is the only planet with life? Human minds aren't good with very large numbers. What seems "practically infinite" to us - isn't, really. The number of all planets in the universe is said to be in the ballpark of 10^24. Meaning (obviously) if you keep on dividing it by 10, in just 24 steps you g…
I wonder how long much longer it will take for the astronomers to get the technology that would allow them to hunt for life in other stellar systems so that we can check all this out.
Depends on the size of the dish, really. You need to resolve the 'signs of life' at stellar distances.
Street-Math time!:
Lets assume that means you need to resolve a meter sized elephant on another planet. Lets choose Vega, as that is ~25ly away, really the furthest star we can go to (and return from) and still have someone alive here to have a beer with afterwards (50 year round trip). 25ly is about 2.3E19 meters away.
A 1 meter sized elephant at 2.3E19 meters is about 4.3E-20 radians.
Lets use wavelengths in the visible spectrum. Hydrogen's Balmer peak at 656nm is a nice red color to look at (though stellar issues abound here).
The resolution of a telescope is approximately : R = L/D. R is resolution, L is the wavelength, D is the diameter. Rearranging we get the diameter to be : D = L/R. Plugging in a L of 656nm (~6.6E-7m) and a R of 4.3E-20radians and you get D.
D is about 1.5E13 meters.
For reference the earth is about 1.2E7 meters, about 6 orders of magnitude smaller. 1.5E13 meters is about 14 light-hours, much larger than the Earth-Sun distance.
Soooooo, I think it's going to be a while ...
;)
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#148Like Carl Sagan rightly said - "Cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself.” We need to study ourselves more to comprehend this vastness.. [1] https://www.sciencealert.com/physicists-show-that-our-brains...
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Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#149Earlier quoted context omitted.
But it's fairly likely to be carbon-based, as carbon is the simplest existing element with the maximum amount of valence electrons. And generally, simpler (= lower ordinal number) means more stable, as well as more likely to arise (as less energy is required, e.g. in stars).
There are other theoretical biochemistry possibilities[1]. Silicon, for example, works well in low-pressure environments. It's an immense stretch of the imagination to think about life-forms that use semiconductors to do useful work, but is certainly a fun thought experiment. [1]: https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemi...
Yes, it's possible, just less likely. How much less likely is hard to tell, but I if you hear hoofsteps, you first think of horses, not zebras.
Re: Observable Universe contains 10x more galaxies than previously thought (2016)
#150Earlier quoted context omitted.
But it's fairly likely to be carbon-based, as carbon is the simplest existing element with the maximum amount of valence electrons. And generally, simpler (= lower ordinal number) means more stable, as well as more likely to arise (as less energy is required, e.g. in stars).
It may not be based on elemental matter, or matter at all.
Hmm, true. But then, interaction with elemental matter life forms (like us) would become terribly difficult; it might be hard to even notice there's a life form existing in anti-matter.