• We hope all of you have a great holiday season and an incredible New Year. Thanks so much for being part of the Space community!

Fermi paradox

Aug 31, 2021
37
16
35
SETI Project is expecting to detect alien signal(s) coming from the deep space? Let us take in the consideration few objects close to the Earth but distant from each other. You can take any object. I have chosen this three:

Proxima Centauri 4 ly.
Kepler-452b 1402 ly.
Andromeda galaxy 2.5 million ly.

In order to detect E.T. signal we must assume that aliens aren`t technologically advanced and that they are stupid enough not to camouflage their communications. I know one such civilization - it is us. Not that we aren`t camouflaging our radio signals, we are even intentionally sending our signals into the space. I consider Arecibo mesage to be one of the biggest foolishnesses ever. I can not understand the idea to send crucial data about human civilization into the space to be available to every malevolent specie existing out there. We still have no shield around Earth to disguise our overall transmission.

Shield, please. Vanity - off.

You believe that aliens communicate with radio waves? You believe that aliens walk around the Universe carrying radio transistors? How naive.

Is there anyone out there? Statistically, it is very probable. Observationally, there is a problem. The problem is described as Fermi paradox or why we haven`t found any evidence of the E.T.? In this text I will forget the Roswell story cause it may or may not be true. Is there any other solid proof? UFO sightings, alleged abductions, ancient engravings depicting mysterious objects and beings, etc., but not a single bit of evidence.

When we look at our Sun - we see the image 8 minutes and 20 seconds old. To see the Sun as it is we must wait for 8 minutes and 20 seconds.

When we look Proxima Centauri - we see the 4 year old image since light traveled 4 light years to reach us. To see how Proxima Centauri looks now we must wait 4 years.

We can never see anything distant as it is at the moment of the observation.

Let us look at the exoplanet Kepler-452b. The image we see now is 1402 years old because it is 1402 ly away from us. 1402 ly is the distance that light travels in 1402 years. How can astronomers on the Earth draw a conclusion that there is no advanced civilization on the Kepler-452b? Or just life? Or anywhere in the Universe? Wait 1402 years and look again to see how it was before 1402 years and then tell me is there aliens or not. Do not claim now what you will see in 1402 years. Andromeda? Well, that image needs to travel 2.5 million light years to reach us.

The argument "we haven`t still detected alien presence" should be degraded into the mere fact that "we are still not capable of detecting alien presence". Hundred years ago, American physicist and radio engineer Karl Jansky discovered radio signals coming from the center of the Milky Way.

Whatever is now we can not see it yet, not soon, perhapse too late.

The true danger lies in the blind self-confidence that we are alone, if not alone that we are supreme, if not supreme that we will have the chance to negotiate.

Question for SETI Project: If we do not see something - does that mean that it is not there or that it could be obscured or that image has not even come to us?
 
Last edited:

Catastrophe

The devil is in the detail
Helio,, you know that if the observed universe is expanding at speed proportional to distance, then light will not reach us. However, I overlooked the fact that this was not the case earlier (my bad).
I shall have to postulate a time when the sky was full of stars. By extrapolating backwards (well known procedure in exact science ;) ) I will postulate a law that says that once the sky was full of something, obviously assuming that there was a sky and hence a planet Earth. In the beginning et cetera.

Back to Fermi. Does his Paradox not assume that stars are eternal, and thus always existed? Would not dead stars (at some point in their back story) block off the light from more distant stars? How about inventing some dark stuff to block off the light - could be proto clouds or dark stuff? Any old stuff will do. Sorry Fermi!

Cat :)
 
Aug 31, 2021
37
16
35
Is there any possibility to see, for example, Kepler-452b as it looks now - not before 1402 years when its light started the journey toward us?


Before starting with the exposure, I must explain few basic terms related to the space measurements.

1) To measure the distance between objects in the space we can use method called trigonometric parallax.

2) If a star is too far away to measure its parallax, astronomers can match its color and spectrum to one of the standard candles (Supernovae type Ia) and determine its intrinsic brightness. Comparing it to its apparent brightness, we can get a good measure of its distance by applying the 1/r`2 rule: The intensity of the light to an observer from a source is inversely proportional to the square of the distance from the observer to the source (an inverse square law).

3) „Red shift“ is a key concept for astronomers. The term can be understood literally - the wavelength of the light is stretched, so the light is seen as „shifted“ towards the red part of the spectrum.


Radial velocity (Doppler spectroscopy) or red/blue shift can be described as stretching and compressing of the light waves. Notion is z, unit is dimensionless since it is a ratio between observed and known values.

The best space images so far were made with the Hubble telescope (Hubble Ultra Deep Field). In December 2021. NASA & ESA will launch Webb space telescope which is going to be the most powerful space optical device ever built by humans. Among all other things, we will be able to make better shots of the Kepler-452b.

We can not see distant objects in the space as they are but only as they were.

One idea that cross my mind, how to bridge the incredible, is that we can apply optical magnification, boosted by the digital tuning of the focal lenght assisted with the Artificial Intelligence image enhancer, using quantum chipset, in order to trace back the origins of the light all the way back to the source. When we achieve that we will be able to look at the distant objects „hoc tempore“.
 
Jun 1, 2020
1,866
1,559
5,060
Back to Fermi. Does his Paradox not assume that stars are eternal, and thus always existed? Would not dead stars (at some point in their back story) block off the light from more distant stars? How about inventing some dark stuff to block off the light - could be proto clouds or dark stuff? Any old stuff will do. Sorry Fermi!
Ah, your'e thinking of Olbers' paradox of not having a white sky. Fermi asks why we haven't had visitors given the no. of star systems and over 13 billion years. This was the precursor (by ~ 10 years) to the Drake Equation, and 45 years before any exoplanet was discovered.

But regarding Olbers' question, over enough time, the radiation from all the stars would heat whatever else is there to the same temperature, thus everything would glow even dead stars. Whatever might block light would eventually get hot enough to glow, too.
 
  • Like
Reactions: Catastrophe

ASK THE COMMUNITY

TRENDING THREADS