With Gliese 581 believing to contain the conditions amenable to the development of life, who likely is it that intelligent life exists in the universe? The Drake Equation seems open to manipulation depending on optimism or scepticism, and even if just one similar planet exists, how would contact occur, given the vast light-year distances between galaxies, while also any messages received could well prove mutually uninterpretable? The likelihood is realistically zero, but with the first radio messages still travelling, we can't definitively state we are alone until the end of the century.
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Calling occupants of interplanetary craft
The Drake equation is more or less meaningless, given that several of the variables are completely unknowable (at present), and that it relies on certain assumptions that may or may not hold. In a sense, the existence of other intelligent life is a binary question. Either it's somewhat likely (as in, loosely, not beyond one over the Avogadro constant) and therefore other intelligent life pretty much must exist somewhere out there, or its vanishingly unlikely, and we're the only exemplar. At this stage of our knowledge of abiogenesis, we have no idea. Regardless, it seems vanishingly unlikely that there's any intelligent life within communicable spacetime.
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Calling occupants of interplanetary craft
and they haven't listened yet.
and, as soon as I disbelieve that, I disbelieve in fairies, or iced buns, or marmite, or myself. And none of the above are likely to happen yet.
I need a miracle...
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Calling occupants of interplanetary craft
A question about travelling beyond light speed was raised here recently, and I said (and was shot down) that I thought it might be possible ... given that we're talking within the confines of what we know as if that (the sum knowledge of our puny species) is the absolute limit of all that is knowable.
So in my way of thinking (based on no laws of physics that we know), "communicable spacetime" has no bounds. At least from the hypothetical 'their' perspective.
On a similar note ... Stephen Hawking was 'interviewed' by Guardian readers recently, and one asked him that if the Universe is constantly expanding, then there must be something beyond it for it to expand into; what was it? He dodged the question. What is beyond the universe?
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- Mar 2008
- 20749
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Calling occupants of interplanetary craft
erwin wrote:
What is beyond the universe?
Anyone who has visited Lisburn will understand.
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Calling occupants of interplanetary craft
then there must be something beyond it for it to expand into; what was it? He dodged the question. What is beyond the universe?
1. No it doesn't. The universe isn't expanding into anything. It's just expanding. It's not a balloon in a box. There is no box. Spacetime itself is expanding.
2. YOu could argue that anything beyond the boundaries of our universe can't be seenmeasureddescribed etc as all the possible ways of measuring indeed, the very terms of reference themselves, are meaningless beyond the boundaries.
3. How big is the coastline of Britain? It depends on the scale of the measuring device. The coastline is essentially fractal. So is the universe perhaps. It's all wound up and wrapped around and twisted together over many dimensions. So size as in heightxwidthxdepth doesn't really mean anything.
Sorry, that's not terrible helpful is it?
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Calling occupants of interplanetary craft
but with the first radio messages still travelling, we can't definitively state we are alone until the end of the century.
We couldn't possibly know. Even the Milky Way, our own galaxy had around 200-400 billion stars and takes light 100,000 years to travel from one side to the other.
There are between 200-400 billion GALAXIES out there. The observable universe is around 90 billion light years across. SO we can see 45 billion light years in any direction. Which means it'll take 45 billion years to know - if someone makes it stupendously obvious like writing hello in manufactured supernovae - only that there was someone here right now. And In those 45 billion years, things change.
So you know, the end of the century may be a bit optimistic, mate.
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Calling occupants of interplanetary craft
Forgive me for self-quoting, but my sister wanted to appear clever to her workmates, so I knocked the following up for her. It really blows my mind just thinking about it...
The Sun is 100 times the diameter of the Earth. You would need 1 million Earths to make up one Solar volume.
The Sun is an average star. Light takes 8.3 minutes to travel the 93 million miles from there to Earth. So when you see the sun, you’re looking back in time, 8.3 minutes.
The fastest speed anything man-made has attained is the Helios probe which flew at roughly 150,000 miles per hour. Light travels further than that (186,000 miles) every single second.
The next nearest star, Proxima Centauri is 4 light-years away. That is, it takes light 4 years to get from there to here. That’s 24 billion billion miles. Or 24,000,000,000,000 (trillion) miles if you like. If we left now at the speed of the Helios probe, we’d arrive around the year 4130AD.
There are between 200 and 400 billion stars in our galaxy the Milky Way. They’re all even further away.
To get from one end of the galaxy to the other takes light 100,000 years. Six hundred thousand trillion miles. So the light we see is light that began its journey around the time Homo Sapiens first learned how to cook.
The nearest galaxy to our own is Andromeda. It is 2.5 Million light years away. That’s more zeros than I want to type.
So when you look at the Andromeda Galaxy, you are looking at how it was 2.5 million years ago. 2.5 million years ago, our distant ancestors were just starting to invent stone tools.
It is however, getting closer at a relatively sedate 500,000 miles per hour. At that speed, Andromeda and the Milky Way will collide and merge in approximately 4 billion years.
These 2 galaxies are at the centre of the “Local Cluster” of galaxies that stretches 10 million light years across. Light arriving at one end from the other today, started around the time we were speciating from Gorillas.
Remember I said that there are 200-400 billion stars in the Milky Way? Well there are at last estimate 400 billion galaxies in the universe. To give you an idea of how many that is, take a 5p piece and hold it up to the sky. Now, stretch out your arm 75 feet. The area of the sky that the 5p piece obscures held up to the sky 75 feet away, holds 10,000 galaxies. Galaxies. Each with approximately 400 billion stars in each.
These Galaxies are flying apart from the Big Bang. Instead of slowing down though, they’re accelerating. We have no idea how or why.
Here’s something even weirder. The Universe is approximately 13.7 Billion years old. The observable universe is 93 Billion light years across. That means that the universe is around 7 times bigger than it should be. The reason for this is that spacetime itself is stretching. Reality, at a fundamental level is inflating like a balloon. Cool huh?
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Calling occupants of interplanetary craft
All of which reminds me that we're finally leaving the Solar System...
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Calling occupants of interplanetary craft
Seconded.
It's spine tingling to consider the amazing research and engineering in modern science. Not just something like Voyager which, given the limitations of the time, was astounding enough but take the Large Hadron Collider too.
It's a machine designed to smash together the smallest possible quantities of matter at speeds approaching the fastest anything could ever travel in order to rip apart the very fabric of existence, and in the debris, see the face of creation itself.
That's just fucking beautiful. Well done us.
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Calling occupants of interplanetary craft
Essentially in the bits and pieces left over from high speed particle collisions
The LHC fires particle beams at each other at almost the speed of light. When they collide the energy levels involved are enormous, approaching Big Bang enormous, and observing what happens in those conditions tells us a massive amount about why the universe is the way it is. Essentially, the LHC allows us to see the what the universe was like a split second after it began.
I mean, I'm just a layman myself and there are people far more informed than me round these parts but that's how I understand it.
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Calling occupants of interplanetary craft
hobbes wrote:
Not even the waiting room of a relatively salubrious dentist's surgery.
As a kid I imagined infinity being sat on our old brown 70's sofa falling through space. Quite a nice place to be with a pile of biscuits & Scooby Doo on.
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Calling occupants of interplanetary craft
I've often thought about what extra-terrestrials would say or how they would act if they finally arrived on Earth, and wondered if they'd do like I would do at times and enter a room intent on doing something but forgetting what it was when I got there.
"Peoples of the planet Earth. We have come from a far-off world from the deepest reaches of the Universe so that we can....
..we can...
...erm...
...ahm...
Bollocks. (Trudges angrily back into spacecraft) Bollocks, bollocks, bollocks!"
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