High resolution transmission spectrum of the Earth's atmosphere -- Seeing Earth as an exoplanet using a lunar eclipse
Its an answer to the age old existential dilemma: are we alone in the cosmos. And would indeed provide a modicum of hope for the future of humanity ;)
Exoplanet hunters rethink search for alien life
https://www.nature.com/news/exoplanet-hunters-rethink-search...
700 LY is practically our backyard and makes it much easier to observe.
Even if we never visit that particular planet, we may learn something useful that tells us something about planets nearby, or even about our own solar system.
At this point, we're just collecting data about extra-solar planets, which we weren't sure even existed until recently. With so many unknowns, it's exciting whenever we can fill in our knowledge gaps just a little bit.
But of course the 'catch' is that time dilation (and length contraction) kick in. And so while from the frame of reference of the ship and all its travelers only 12 years will have passed, from the frame of reference of everybody back on Earth - 700 years would have passed. What we would observe is that as the ship approached the speed of light, its apparent mass would approach infinity, reaching a velocity asymptote at the speed of light.
And these values are also not linear. It's possible to travel a practically unlimited distance in the span of a single human lifetime - from the perspective of that human. 100 trillion light years would take about 62 years at 1g from the perspective of those on board our ship. There's also really really fun paradoxes available here. Imagine somebody leaves Earth towards this planet and at some point decades, or perhaps even centuries later, we develop technology that enables substantially faster travel. Our planetary settlers on their 12 year journey could arrive 12 years later to find that not only is the planet indeed colonized, but it's colonized by the descendents of Earthlings that left decades, or even centuries, after they did.
The really exciting thing here is that NASA seems to have gone silent on the EM drive after having it pass every single test they threw at it. In my opinion, this is evidence of classification which is something that would make sense. If the EM drive somehow actually works - and everything we know says it most certainly should not - that would change absolutely everything. The ability to actually start realistically considering these sort of missions would be mundane compared to other possibilities, which I'm not even going to get into as they sound, and should be, absurd. As an aside, this part on the EM drive is 100% speculation - not to be confused with everything stated above, which are direct and heavily tested (even if absurd sounding) consequences of relativity.
It is absolutely a limit on effective travel (if we ignore things like wormholes for a second). Conventional motion through space is bounded by c for several reasons, not the least of which being that the closer you get to c, the more energy it takes to make smaller and smaller changes in velocity (the object acts as though it's gaining mass the faster it goes). In fact, it's asymptotic. Accelerating a particle to c would require an infinite amount of energy.
You are currently moving at near the speed of light relative to many things at this very moment, yet your mass is certainly not approaching infinity, America notwithstanding! And if you accelerated enough in the opposite direction of your relative partner to exceed the speed of light it's not like you'd suddenly start finding it impossible. No, it's a matter of observation. From the other particle's perspective it would see your mass approaching infinity and your speed would slow, but the distances you covered would remain the same due to length contraction.
A similar effect explains why, for instance, particles in CERN's reactors travel distances that should be impossible for them to travel before decaying. E.g. if the speed of light was 10m/s and a particle decays after 3 seconds then it should be impossible to see that particle travel more than 30 meters. Yet we see it travel hundreds of meters. Isn't relativity fun?
In short, you can't go faster than light in any reference frame, relative to any other observer.
Here's another source: https://physics.stackexchange.com/questions/75501/lorentz-an...
As you accelerate more and more you will never observe yourself or anything else exceeding the speed of light. Instead what will happen is that time will begin to slow down and distances will begin to contract. If in our frame of reference a distance is 100 meters, it would begin to seem to be, for instance, 10 meters.
And the people observing you will also never see you exceed the speed of light. Instead they will see you approach it, and then start to level off asymptotically. Both views are correct. Time itself is what changes. From the perspective of the observer, time will be moving more slowly for the observed. e.g. this is why particles at CERN travel vastly greater distances than they 'should' be able to before decaying. Imagine what it would be like to experience that travel from the particle's perspective.
This is why we see our particle last much longer than it should. And if humans could live for 1500 years, this is why we would see things like our ship make it's 700 light year journey, and then beam back a message that would only hit us 1400 years later - telling us that they're safe and sound and got there in 12 years. Quite fun stuff!
Put another way, this would be the timeline of our ship in years from its perspective and from earth's perspective:
0 earth relative = ship leaves
0 ship relative = ship leaves
700 earth relative = ship arrives at planet
12 ship relative = ship arrives at planet
1400 earth relative = message from ship on planet arrives at earth
712 ship relative = message from ship on planet arrives at earth
This is the most counter intuitive thing about relativity, and time dilation. It's not some 'trick' or matter of perspective. Time itself does literally move at different rates for different people in different scenarios, even when we're all in the same universe. Our ship pilot could make the 12 year journey back and indeed 1400 Earth years would have passed in the interim, and if was somehow able to measure the age of the other planet - 1400 years would have also passed there as well. Even though he himself had only aged 24 years.
Should we achieve the ability to reach relativistic rates of travel - some people may get their wish. Expect huge chunks of the rich to up and leave 'to the future' (from our perspective we'd just see them constantly zipping around near the speed of light... for centuries) in hopes of discovering if humanity has overcome mortality by then! Reality is much stranger than fiction.
> The speed of light is not a speed limit on effective travel, but on observation.
Which is absolutely factually false.
There tend to be three groups of people:
- Those that accept things at face value, which is quite silly. What I'm saying should challenge all intuitive notions of reality making open acceptance simply bizarre.
- Those that reject things at face value. No better than the first and generally driven by an extremely superficial understanding of physics. As Feynman phrased it, people sipping martinis at a cocktail party and discussing relativity, "Ah yes.. how insightful. Though I think some things may indeed be inherently correct. Mmm..."
- And those with a strong physics background already, to whom you provide no additional value to anyhow.
You’re missing a couple of zeroes there ;)