When fantasy becomes reality?

Proto · Jul 21, 2003

>>how would anybody know?

it could be estimated by seeing the velocity stars separate from each other. I don't have the number though.

the Hulk · Jul 21, 2003

Ingenius,but thats pretty scientific but it could be done.

Boltzmann · Jul 22, 2003

finalight said:
how fast do universe grows?

The universe's recession speed is measured by Hubble's constant (Ho)*
The currently accepted value to it is around 50-100 km/s/mpc (mpc = megaparsec). There's so much uncertainty in it's precise value due to uncertainties in the distances of tertiary calibrators (that's the main problem). Note that the value of Ho is directly related to the critical mass needed to "close" the universe (the greater Ho more mass is needed).

EDIT: I forgot to add that since the universe is isotropic and homogeneous the recession is speed is greater for galaxies that are more distant from us (this holds true for every observation spot in the universe - as you can easily tell by the isotropy requirement).

*Ho isn't a constant strictly speaking, since it changes it's value over time, for two reasons: 1. gravity attracts, slowing down the expansion. 2. A possible non-zero cosmological constant, which actually accelerates the expansion.

Kraelis · Jul 22, 2003

*Looks at Boltzmann's posts and bows down in reverence*

K.I.L.E.R · Jul 22, 2003

Okay, so lets get on to the topic about different lifeforms.

There is speculation that our Earth was smacked by all manner of asteroids and comets 3.6 billion years ago. It is said that between 3.6 billion and 3.9 billion years ago (estimate) is when life started forming on our planet.

The reason is that bacteria and other living organisms started to mutate and form and evolved.
While this was happening, who can say that it isn't happening right now on another planet?

Scientists have argued the best ways of searching for lifeforms through different means.
Effectiveness of infrared telescopes of picking up earthlike conditions on other planets is crap at best.

While detecting ozone and methane is far more effective. I have no idea how they can do that but I read a 5 page article about how NASA can go about detecting earthlike substances on other planets.

The thing is, different lifeforms may live differently from us and may breathe and eat differently as well. That's even if they are capable of breathing.
Since they have different accomodations, than we may be looking in the wrong places for life.

tenedia · Jul 22, 2003

and yet, human causes harm to the their homeland; Earth

Exodus · Jul 22, 2003

K.I.L.E.R said:
There is speculation that our Earth was smacked by all manner of asteroids and comets 3.6 billion years ago. It is said that between 3.6 billion and 3.9 billion years ago (estimate) is when life started forming on our planet.

so then its possible the bacteria came off the asteroid. so somewhere else must be sprouting life as well. it wouldn't make sense this was the only planet harboring life. ha, seems like planets are just eggs waiting to be fertilized by asteroids.

Boltzmann · Jul 23, 2003

Exodus said:
so then its possible the bacteria came off the asteroid. so somewhere else must be sprouting life as well. it wouldn't make sense this was the only planet harboring life. ha, seems like planets are just eggs waiting to be fertilized by asteroids.

There's a specific theory concerning this, and it's called panspermia. It says that life probably came out from outer space, through meteors. Some great physicists supported it (Sir Fred Hoyle, for example).

Let me give my own thoughts on this speculation about the probability of life.

First, life appeared on Earth when it was almost 2 billion years old (1.8 billion years - date of the first bacteria). This is more than enough time for purely stochastical processes do the job (not that this really counts as evidence against panspermia, but it makes it somewhat unncecessary).
The next critical step in life's evolution was evolving from a prokaryotes to eukaryotes.
Brandon Carter applies anthropic reasoning to these issues in two papers: "The anthropic principle and its implications for biological evolution" and "The anthropic selection principle and the ultra-Darwinian synthesis." They are very interesting, as he assess the number of critical steps needed from a purely probabilistic standpoint. As far as his paper goes the situation don't looks so bad in terms of epistemic probability - that is the events that lead to intelligente life aren't that improbable.

K.I.L.E.R said:
While detecting ozone and methane is far more effective. I have no idea how they can do that but I read a 5 page article about how NASA can go about detecting earthlike substances on other planets.

Not so hard to do if you know a thing or two about spectroscopy. This is the method used to detect the exact ammounts of specific elements in stars and on the universe in general. Of course it's trickier for planets, but can be done with the proper methods.
I wish I had a good observatory and a lab available. I need to improve my practical knowledge of these techniques.

Given the high number of planets in our galaxy our best bet in finding signs of extraterrestrial life is through radiotelescopes. But it will take some time before we find any evidence - if we find any evidence at all.

Skye · Jul 23, 2003

Just for those who weren’t paying attention in science class, The Law of Conservation of Energy states that matter can never be created or destroyed. However, energy when used up in its current form will take on another form. So you don’t have to be afraid of the universe using up all it’s energy because quite frankly it can’t happen. The same thing applies to matter. For example you could've ate part of a dinosaur's poo hundreds of millions of years old in your breakfast/lunch/dinner today.

Boltzmann · Jul 23, 2003

Not really an important point. Although energy can't be destroyed some other things just as bad can happen. Namely:

1. All the current negentropy endowment of the universe being converted to entropy. Thanks to the 2nd law of thermodynamics this is bound to happen in the far future (something like two trillion years is an acceptable ballpark).

2. A corollary of (1) (when coupled to the Doppler effect) is that given enough time all forms of energy within the universe will have a redshift so high as to be unusable in any form.

So from a practical standpoint our long term prospects are the same whether energy can efectivelly be destroyed or not. Of course it cannot be destroyed, as stated by the 1st law of thermodynamics, but the practical results are just the same.

Skye · Jul 23, 2003

Yes, the universe right now is being converted to entropy. It has been since the moment of the big bang. Entropy occurs with everything and anything. Even at a faster rate under a closed universe.

Boltzmann · Jul 23, 2003

In fact you should say that total entropy is increasing (while negentropy is decreasing) over time. As argued by Hawking (and Boltzmann

) the arrow of time as measured by us is directly related to entropy increase.

Kazuya · Jul 23, 2003

Boltzmann said:
1. All the current negentropy endowment of the universe being converted to entropy. Thanks to the 2nd law of thermodynamics this is bound to happen in the far future (something like two trillion years is an acceptable ballpark).

In english please :eyespin:

Boltzmann · Jul 24, 2003

Kazuya Mishima said:
In english please :eyespin:

Guess I got a bit carried away by the terminology

To say it in a simple way (although I would be mercilessly slayed by physicists if I said that this is strictly accurate) I should say that the degree of disorder in the universe as a whole is growing over time (negentropy would represent ordered patterns in this description).
Another way to say it is that signals are being randomly degraded into heat, and that it's a one-way process. After all, entropy is a heat-generating process.

And my second statement was a direct consequence of Hubble's law (which I stated a few posts above), where a galaxy's recession velocity is directly to proportional to it's distance from us.

Takmadeus · Jul 24, 2003

Actualy..... sme years ago, I was watching a show on Discovery channel, and it seems that the universe is not only growing, but acceleratingits speed each time more...... why is it doing that and how, I don't quite remember, but I think it was due to some weird energy particles that speed up the substance in the universe..... but going back on topic....

well, it is really possible for uindead to exist in another universe...... as accepting that theory means allowing anything to happen in a different universe, including the impossible things..... one of those things is the existence of magic....... I don't know... but the expanation given to magic existence in ff8 made me wonder... and analyzing that excplanation made me think itis actually possible to create such powers and t be controlled and harnessed by humans (like some sort of magitek technology)...... it is just that our technoogy hasn't grown enough to make that remotely possible...... but it does not mean that the existence of technology that can generate "magical" effects is not possible..... I guess you get my point...

K.I.L.E.R · Jul 24, 2003

So basically we are going to spontaneously combust.

j/k

I also would like to make it clear that if we do spot any life then that life would have to be very close to us. Detecting life in the stars when the stars could be billions of years old won't be very helpful in getting us to communicate with the lifeforms. They could even be extinct by the time we get to them. :lol:

I don't doubt for 1 second that there is life out there. I don't need proof to know that. What I do need to know is, are we ready to meet other lifeforms?
Communication is going to be very funny if all we are going to talk in is PI. :lol:

REi_FoX · Jul 24, 2003

theres a possibility that some other lifeforms exist on far away planets...

well recently astronomers found a new planet and it has its own sun just like ours!

and the shape on the planet is 4X the size of Jupiter

K.I.L.E.R · Jul 24, 2003

That planet isn't liveable on anymore. Especially considering the time lag between our telescopes and the planet. That planet might not even exist for all we know.

REi_FoX said:
theres a possibility that some other lifeforms exist on far away planets...

well recently astronomers found a new planet and it has its own sun just like ours!

and the shape on the planet is 4X the size of Jupiter

REi_FoX · Jul 24, 2003

well NASA said it exist... well what im pointing at is in other galaxies some microrganisms or let just say living creatures might exist...

and of course they adapted to their own environment

Sera · Jul 24, 2003

just wondering...if we use a to telescope to find far far away planets, are we sure that the time we are seeing it, is also the time it is being seen, i mean,
just like killer said the time lag on between planets can be a factor..

When fantasy becomes reality?

Proto

the Hulk

Boltzmann

Kraelis

K.I.L.E.R

tenedia

Exodus

Boltzmann

Skye

Boltzmann

Skye

Boltzmann

Kazuya

Boltzmann

Takmadeus

K.I.L.E.R

REi_FoX

K.I.L.E.R

REi_FoX

Sera

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