Quite interesting interview from Jeff Bezos: https://www.geekwire.com/2018/jeff-bezos-isdc-space-vision/
Astronomy & Space Exploration
- Thread starter MrMarcello
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There is no Fermi paradox: https://arxiv.org/abs/1806.02404
There is no advanced civilization in the observable universe(Kardashev 2 or more). We would be able to see their impact in the brightness of the stars in the galaxies comparing in the infrared. Humans need to colonize the galaxy.
I have an issue with the Kardashev scale in that it is entirely anthropocentric - its a measure of life based on the way the human brain perceives the Universe. We define life as biological and carbon based and then go on to assume advanced life should be able to harness technology to do x or y (assumed in Kardashev scale). We can't be sure whether any of that is the correct approach to analyze life elsewhere.
I dont take the Kardashev scale as an absolute. Its just a minimum ground to establish an argument because we really dont know at this point.
But there is some truth that is inevitable: laws of Physics are the same everywhere. The resources to sustain an advanced civilization and the energy needed will come from their stars. Unless they can figure out how to produce anti-matter or use dark energy. But this probably would take superior science than what you need to build a Dawson Swarm.
The technology that humanity have today is enough to build some form of Dawson swarm. You dont need any sci fi tech. It would be just a variation of the Nasa Probe mission to the sun. And we would see any civilization starlifting their sun in the Milk Way. There is nothing there
That's one of the issues I have with concepts like Kardashev, Fermi etc. The laws of physics may be static to us but we can't discount the idea that we haven't yet fully uncovered the true nature of the Universe. We don't yet have a theory of everything, we don't know the size of the universe, the nature of gravity, how dark matter and energy work etc. Everything we know is relative to the current evolutionary threshold of our brains. We can't therefore presume that life elsewhere is constrained or imbued by our evolutionary journey or even whether or not it is biological or carbon based.
Mostly in agreement with @Raoul here, I think we're far too human-centric, if not Earth-life centric when making assumptions about the nature of alien life; be that in their biology or in the way their technology evolves. While it's true that we're all bound by the same laws of the universe, the unknowns of the cosmos by far outweigh the knowns.
Also, with regards changes to light as a hallmark of advanced civilisations - surely for the worlds several thousand light years away or more (i.e. almost everything) we couldn't yet observe any changes a potential young civilisation has made.
Also, with regards changes to light as a hallmark of advanced civilisations - surely for the worlds several thousand light years away or more (i.e. almost everything) we couldn't yet observe any changes a potential young civilisation has made.
The observable universe? I can buy the idea that there are none in the Milky Way (although I don't really buy it; there's a lot of the Milky Way we can't even see, for one), but we really haven't got a very good grip on what goes on 47 billion light-years away. We're still discovering new types of stars and star systems for crying out loud, so it's absolutely, categorically not possible to conclude that there is no civilization out there harnessing their own star.
And it's not like we have a lot of stars under constant supervision. If some civilization 20 billion light-years away has their star under wraps, that might simply look to us as if it's a different kind of star.
Dyson Spheres always sounded like a really stupid idea quite frankly. The amount of materials required would be mindblowing, and it presupposes that we'd have some need for the staggering quantities of energy involved. Why exactly? As we develop nanotechnology and new energy technologies, isn't it perfectly likely that we'll discover new ways to reduce rather than endlessly expand our external energy requirements? We have sources of energy around us in the world every second of the day, but we just don't have many ways of actually using them yet. We're already working on fabrics that generate energy, different ways to harness solar etc etc. Plus we may still have fusion power to come, and then goodness knows what kind of future technologies that might be even more efficient.
If the best method we've got for trying to determine whether civilizations exist is 'have they built a sphere or swarm around their sun' then we're probably wasting our time really.
If the best method we've got for trying to determine whether civilizations exist is 'have they built a sphere or swarm around their sun' then we're probably wasting our time really.
Comparing the visiblle light o any galaxy with the information in the infrared and you can see that there is no brightness missing and no apparent impact of an advanced civilizations in the stars.
So there's no advanced civilizations in the observable universe because we haven't noticed any irregularities in the brightness of stars in the Milky Way yet? Sorry mate but that sounds extremely daft.
You've done that with every galaxy in the observable universe, then? Every galaxy within a 90 billion light-year diameter? Again, you're being way too confident about this. This is not some settled matter.
All we know is that we haven't found any evidence for other intelligent life in the universe so far and that shouldn't surprise us. Any claim about this goes along with a gigantic level of uncertainty, that makes it hard to say any sensible thing at all. Using common sense to reason about this is pointless.
That said the current understanding of the computational nature of our brain, information theory and the origin of life would all point in the direction that alien life would be similar to our own in important aspects.
The caveat would be the issue of consiousconss, that nobody understands to a sufficient degree to take it into account.
That said the current understanding of the computational nature of our brain, information theory and the origin of life would all point in the direction that alien life would be similar to our own in important aspects.
The caveat would be the issue of consiousconss, that nobody understands to a sufficient degree to take it into account.
I tend to agree with this. What would be the purpose of harnessing the energy of our star beyond what we already do to power our planet in the present ? Unless the sun can provide us with some sort of ridiculously fast propulsion technology that we don't yet know of then what's the point.
We are not looking at the entire universe though. In fact, we are looking in only a small fraction of our galaxy, and we know next to nothing about stars in other galaxies.
Physics was mentioned in a few posts recently... is it plausible that the laws of physics as we know it could change in other galaxies due to varying factors, like say dark matter?
Likely not in other galaxies but in other Universes - such as pocket universes proposed by Alan Guth's work on inflation, where new pocket universes are being created with potentially different laws of physics.
http://www.dailygalaxy.com/my_weblo...ferent-physical-laws-todays-most-popular.html
As far as the Kardashev Scale goes, its not necessarily about the actual practical applications of a Dyson Sphere existing but rather an illustration of a civilization's maximum technological capacity of harnessing energy to be capable of building one that is relevant
More than likely no. Laws of physics are either universal or we have totally misinterpreted them and don't know anything about them.
As Raoul said though, in other possible universes, the laws of physics and universal constants might be different.
Dark matter doesn't seem to interact much (if at all) with ordinary matter in any other way than gravity, so it's very unlikely it could have any sort of effect that you're thinking about. And nearly every galaxy has dark matter in it, because dark matter is integral to those galaxies forming in the first place.
Like the others have said, all bets are off concerning other universes, but that is something we will never be able to know so any speculation truly is just speculation.
And how possible is this? Perhaps we have say gravity and/or time wrong.
Never say never.
Okay, but only to the point where you could say "never say never" about literally anything. Other universes is not science at this point, because there are no predictions to be tested. I wouldn't put it in the same category as even stuff like "what if it's possible to travel through wormholes" or "what if we could harness dark matter", or anything involving the singularity of a black hole. Those are all nearly complete unknowns at this point, but there's still science involved.
Yep, that's probably the most interesting takeaway: ~13 times the mass of Jupiter, but only ~1.2 times the diameter — it's almost exactly at the lower end of the the Hydrogen to Deuterium-Burning Mass Limit. For now, they've classified it as a planet:
http://www.astronomy.com/news/2018/08/free-range-planet
So if SETI received a signal from an alien civilisation, what's the worst possible message we could get?
1. Beware, they are coming.
2. Help us
1. Beware, they are coming.
2. Help us
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MAGA