Sure, but several people have brought this up as “an interesting possibility”, and all of them have shyd away from saying ET. So they didn’t confidently or unambiguously state it, but that’s kinda the implication and where their head is at.

IIRC the proper answer is “we don’t know the origin, but we haven’t had any reason to think they came from space”.

Oh OK. Well that explains why you see things the way you do I guess. :)

Funny how no one bats an eye when a german shepherd sniffs out a missing person based on almost undetectable particles or a bird knows exactly which direction is north, but we scoff at the idea that there may be ways to communicate with your brain alone. Why? Because that’s the stuff of TV and movies – fiction. Culturally, I think we’ve been so disheartened by our inability to realize our most extravagant dreams of the future (hovercars and etc) that we have basically fallen into thinking that the mere existence of a topic in science fiction discounts its credibility as a real-world subject. This is why we get articles like “Scientists say they are closer to Star Trek Warp Drive”, where everything must be tempered just in case. We don’t want to look like we actually believe in Science Fiction, now do we?

> in a single lifetime

There’s some wiggle-room there. A species that is naturally biologically immortal (or had biology that supported long periods of inactivity) might not find that spending hundreds of years to travel to a nearby star system was a deal-breaker for interstellar travel. They might be more motivated to execute such a project than we are since they could not just wait for their ancestors to die of old age as a way for younger members of the species to have control.

Also there is a possibility that a species might develop the technology to create a partly or fully artificial version of themselves that makes long interstellar trips less of an obstacle (synthetic biology, a combination of biology and machine, pure machine, etc).

Natural humans are certainly poorly suited for interstellar travel, but it may be that other kinds of life are more tolerant of it, or have redesigned some members of their species to handle it.

And you clearly did not read my post?

The time dilation effect is pretty well known and comes naturally from the equations of the General Relativity Theory.

It’s also been proven experimentally in particle accelerators (like CERN) when particles with at rest very short and well known half-lives (i.e. they natural break down into other particles some time after being created) lasted a lot longer (from our point of view) when travelling at near light speed.

However that effect only really starts getting noticeable without special equipment when the speed something is travelling at is getting near the speed of light (something like 90% or more of light speed).

This works correctly for the example of the previous poster because the distance to Sirius is given in light-years, which is literally the number of years that takes light (which by definition travels at the speed of light) to travel that distance.

(By the way, from the same equations from were you get time dilation comes that from the point of view light the trip is instantaneous)

So yeah, travelling a distance of that takes light 9 years to travel would be theoretically possible to do so fast (near light speed) that it would seem for those doing the trip to only take a few months (even though for those outside it would still seem to take longer than 9 years - as it takes light 9 years to get there so something at sublight speeds would take longer than the 9 years that takes for light).

Yeah, this is highly counter intutive so it “feels” wrong. If fact, the whole General Theory Of Relativity is highly counter intuitive. Yet, quite independently of what intuition (which is just a destilation of our personal experience) tells us, all that we’ve been able to observe so far in applicable situations is things happenning as predicted by that theory, not “intuition”.

I’ll put it another way then: any information you intended to send back after you arrive in Sirius would take ~9 years to arrive back home. Due to causality, this means that you cannot interact with Earth in any way for – at minimum – 9 years. However, from your perspective, you accelerated at let’s say 10 Gs (speed increased by 98 meters per second every second), until you were half-way to Sirius, which will take about 5 months. Then you decelerated at -10 Gs to arrive with 0 speed, another 5 months. You perceive only 10 months of travel, but you are now 9 light-years from home.

The math is not the part which is difficult, and requires only a basic understanding of relativistic physics. The issue is maintaining 10 Gs of constant acceleration for 10 months.