Scientists detect water on exoplanet

Mar 2019
1,650
Kansas
#31
True, probes have found out that the planet has got a very weak magnetic field, but it's not generated by its core: it the result of the interaction of the solar wind with the ionosphere [and it's so weak to be irrelevant]. But Venus is anyway an extreme case [even if there are projects to terraform it].
Yeah we would need to have a definitive understanding of volcanism on the planet before throwing money into something like that. Venus really is the red headed stepchild of the solar system :(
 

Edratman

Forum Staff
Feb 2009
6,695
Eastern PA
#32
All of these investigations are predicated upon alien life similar to life on earth.

That is naturally a two sided argument in that there is no evidence of any other type of life other than carbon, water based but on the other hand, there is no evidence that other forms of life are untenable.
 
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AlpinLuke

Forum Staff
Oct 2011
26,889
Italy, Lago Maggiore
#34
All of these investigations are predicated upon alien life similar to life on earth.

That is naturally a two sided argument in that there is no evidence of any other type of life other than carbon, water based but on the other hand, there is no evidence that other forms of life are untenable.
You know ... science is based on observation and experiment. Mars tells us that silicon superior species are not possible in reality [Mars is perfect for aliens with a biology based on silicon]. May be in other solar systems this is possible.

Now ... the real key to consider is the star. The kind of spectrum of the star determines almost all [with all probabilities also the structure of the genetic code], so that in this solar system only carbon based life forms should be possible.

In any case, silicon based life forms are theoretically possible on planet orbiting around quite uncommon stars. Sure not around a star like the Sun.
 
Aug 2017
198
USA
#35
Warp speed is used by cosmologists to explain "inflation" in the the first second of the Big Bang. Otherwise the whole theory doesn't work. So I assume it's real. By "warp" it means it warps space-time itself which is allowed. We are not traveling in space-time but stretching it somehow. I understand that if you go faster than light this way, you don't have the the time reversal. So say warp111 +/- , x c to get there in a few hours. If you think that's crazy, cosmic inflation was almost instantaneous if you accept the theory which most cosmologists do.
As someone who's fairly familiar with Cosmology due to courses I've done in General Relativity, I can assure you no cosmologist talks about "warp speed" in the context of inflation.

The speed of light in a vacuum is most certainly a constant (up to all known physics), whether it is near black holes or not. I have absolutely no idea why you think black holes contradict this at all. It is certainly impossible (up to all known physics) to go faster than this speed.

It's always good to discuss these sorts of things, but maybe we should be a little bit more aware that general relativity (and even just special relativity) is hard, that an intuition based on a couple of newspaper articles is no where near enough to even have a superficial understanding of it, and we should try to avoid falling into the Dunning-Kruger trap.
There's an important qualification to be made here. In special relativity, a given observer has the luxury of a single inertial frame filling the entirety of spacetime with respect to which they can conduct measurements of times and distances using the Minkowski metric. As such, it makes sense to talk about the speed of light as a "global" constant in SR. In general relativity however, you are no longer guaranteed such "global" inertial frames due to the curvature of spacetime, only local ones (crudely speaking, in a sufficiently small patch of spacetime). If an observer were in a gravitational field, no matter how strong, they would measure the speed of light to be "c" locally but different from "c" away from this local frame.

This isn't to contradict what you said, but just to provide additional context.
 

stevev

Ad Honorem
Apr 2017
3,454
Las Vegas, NV USA
#36
As someone who's fairly familiar with Cosmology due to courses I've done in General Relativity, I can assure you no cosmologist talks about "warp speed" in the context of inflation.
I stand corrected. This paper does discuss both in terms of FTL events and the common explanation is that spacetime itself is stretched without violating the universal speed limit. That was the only point I wanted to make in the context of our interest in a planet 111 light years away. In fact we have a moon of Jupiter, Europa, which has an ice covered ocean just waiting to be explored (post 33) and no warp drive is needed.

FTL Technologies and Inflation Theory
 
Last edited:
Jul 2016
1,308
Dengie Peninsula
#37
The Leonov crew flees Jupiter as a mysterious dark spot appears on Jupiter and begins to grow. HAL's telescope observations reveal that the "Great Black Spot" is, in fact, a vast population of monoliths, increasing at an exponential rate, which appear to be eating the planet. By acting as self-replicating machines, these monoliths increase Jupiter's density until the planet achieves nuclear fusion, becoming a small star. This obliterates the primitive life forms inhabiting the Jovian atmosphere, which the Monoliths' controllers had deemed highly unlikely to ever achieve intelligence, unlike the aquatic life of Europa.

As Jupiter is about to transform, Bowman returns to Discovery to give HAL a last order to carry out. HAL begins repeatedly broadcasting the message

ALL THESE WORLDS ARE YOURS – EXCEPT EUROPA.
ATTEMPT NO LANDINGS THERE.
(2010, Odyssey two.) Arthur C. Clarke.
Here is your warning!
 
Mar 2018
756
UK
#38
You know ... science is based on observation and experiment. Mars tells us that silicon superior species are not possible in reality [Mars is perfect for aliens with a biology based on silicon]. May be in other solar systems this is possible.

Now ... the real key to consider is the star. The kind of spectrum of the star determines almost all [with all probabilities also the structure of the genetic code], so that in this solar system only carbon based life forms should be possible.

In any case, silicon based life forms are theoretically possible on planet orbiting around quite uncommon stars. Sure not around a star like the Sun.

It is an outrageously over confident claim to say that Mars would be ideal for silicon based life, or that only carbon based life is possible around a type G star. How can we possibly know that?? Do you have a citation for that? I'd like to know which scientists and journal I should lower my opinion of.

It might be true if you try and copy our biology substituting every carbon atom for a silicon one, Mars would be good, but why is that the only type of silicon life possible? Do we really believe that we have all possible chemical pathways so well understood that this is the only type of silicon based, replicative reactions possible? For that matter, why should life be chemically based at all? Perhaps you can have complex and self replicating electric storms in the atmosphere of gas giants that have all the properties of life. Or in the heart of neutron stars, all sorts of unknown reactions between quarks could take place that are analogous to those of amino acids. The time scales could be utterly different so that even intelligent life could have a thousand generations in a fraction of a second. We shouldn't think of aliens as "like us, but blue and with more arms" or even of, "like our bacteria, but with different chemistry". We should accept that it could be utterly different.


Science is based on observation and experiment. We have one data point about the kinds of planets life likes (and a handful about what life doesn't like). An extrapolation from a single point is fool hardy. A confident extrapolation from a single point is entirely risible.
 
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AlpinLuke

Forum Staff
Oct 2011
26,889
Italy, Lago Maggiore
#39
It is an outrageously over confident claim to say that Mars would be ideal for silicon based life, or that only carbon based life is possible around a type G star. How can we possibly know that?? Do you have a citation for that? I'd like to know which scientists and journal I should lower my opinion of.

It might be true if you try and copy our biology substituting every carbon atom for a silicon one, Mars would be good, but why is that the only type of silicon life possible? Do we really believe that we have all possible chemical pathways so well understood that this is the only type of silicon based, replicative reactions possible? For that matter, why should life be chemically based at all? Perhaps you can have complex and self replicating electric storms in the atmosphere of gas giants that have all the properties of life. Or in the heart of neutron stars, all sorts of unknown reactions between quarks could take place that are analogous to those of amino acids. The time scales could be utterly different so that even intelligent life could have a thousand generations in a fraction of a second. We shouldn't think of aliens as "like us, but blue and with more arms" or even of, "like our bacteria, but with different chemistry". We should accept that it could be utterly different.


Science is based on observation and experiment. We have one data point about the kinds of planets life likes (and a handful about what life doesn't like). An extrapolation from a single point is fool hardy. A confident extrapolation from a single point is entirely risible.
It's persuasion of mine and you can define it risible. I infer from the observation of what we can see around us that on Mars there are no silicon based life forms; no probe has found them or something similar to a bacteria like this who lives on Earth GFAJ-1 - Wikipedia ... to say all I'd say that silicon based life forms are almost impossible, as for we can know today, even if that bacteria ... presents an interesting substitution of a chemical element with an other and that substitution is what would heppen if a life form substitutes carbon with silicon ... arsenic and phosphorus are as similar as carbon and silicon, but there are scientists who exclude that silicon could substitute carbon: when silicon oxidizes it's solide ... it's silicon dioxite.

But when carbon oxidizes--or unites with oxygen say, during burning--it becomes the gas carbon dioxide; silicon oxidizes to the solid silicon dioxide, called silica. The fact that silicon oxidizes to a solid is one basic reason as to why it cannot support life. Silica, or sand is a solid because silicon likes oxygen all too well, and the silicon dioxide forms a lattice in which one silicon atom is surrounded by four oxygen atoms.
Could silicon be the basis for alien life forms, just as carbon is on Earth?
 
Mar 2018
756
UK
#40
It's persuasion of mine and you can define it risible. I infer from the observation of what we can see around us that on Mars there are no silicon based life forms; no probe has found them or something similar to a bacteria like this who lives on Earth GFAJ-1 - Wikipedia ... to say all I'd say that silicon based life forms are almost impossible, as for we can know today, even if that bacteria ... presents an interesting substitution of a chemical element with an other and that substitution is what would heppen if a life form substitutes carbon with silicon ... arsenic and phosphorus are as similar as carbon and silicon, but there are scientists who exclude that silicon could substitute carbon: when silicon oxidizes it's solide ... it's silicon dioxite.



Could silicon be the basis for alien life forms, just as carbon is on Earth?

I'm not sure why you quoted my post, you ignored every point I made? If you can think of a set of chemical reactions that use silicon that give rise to something that looks like life, well done, you've proved that Silicon based life is at least possible. If you don't find such a chemical reaction, you have shown nothing at all. Just because I can't find my favourite t-shirt doesn't mean that the t-shirt doesn't exist. It *could* mean that, but it could also mean that I haven't looked well enough. So what if there's no silicon based life on Mars? There's no carbon based life on the moon, but that proves nothing at all.

I infer from the observation of what we can see around us that on Mars there are no silicon based life forms; [...] [therefore] I'd say that silicon based life forms are almost impossible
Are you familiar with xkcd?


Precisely the same logical falacy. To paraphrase the common archaeological idiom, "Lack of a proof for a statement being true is not a proof of the statement being false".
 
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