Showing posts with label space travel. Show all posts
Showing posts with label space travel. Show all posts

Monday, May 2, 2022

Surveillance From Space?—Part 1

In two recent blogs I very briefly summarized the history of UFOs—noting that, after all the decades of investigations by the US government, most (about 95%) sightings can be explained by natural phenomena or human aerial activities. There is, however, a small proportion (about 5%) of sightings that cannot be explained, so have a credible possibility of having at least an unknown or even an extraterrestrial or outer-space origin. 

I choose the term “extraterrestrial,” here, in order to indicate that, in the government’s opinion, these sightings do not seem to point to any technology likely to have yet been developed on Earth. That finding could possibly point toward outer-space visitors. Moreover, that possibility is also what readily occurs to us humans—given our long history of speculating that life may have originated elsewhere. Many books and stories have been spawned by this notion.


So in this posting I will consider some of the features that might be associated with visitors from space—without necessarily attributing the currently unexplained UFO sightings to alien visitors. My intent is to step back, suppose that life did arise elsewhere, that that life did achieve a technological proficiency allowing space travel, and has decided to visit Earth. 


One conundrum that I described in my previous posting on UFOs is that, thus far, there is no irrefutable evidence of other-worldly visitors in the way of either a clean photograph, a chunk from an alien space ship, or a piece of their trash. That lack of solid verification causes many skeptics to doubt we have been visited. A similar conundrum exists in the field of the search for extraterrestrial intelligence (SETI): despite decades of searching space for the potential existence of aliens, no signals have yet been detected. It raises the question: If they're out there (or have come here), why have we not yet irrefutably detected them? These are vexing questions.


So, let's suppose that we might have been, or soon will be visited by alien space visitors. What might we assume about them, or what questions might come to mind about them?


  1. Their technology has to be much more advanced than ours, just to have been able to traverse the vast distances.
  2. Why have they not made contact? Why are they seemingly hiding from us?
  3. Do they have some sort of Prime Directive—as posited on Star Trek—whereby they have a strict prohibition on interfering with the evolution of inferior or developing species? The Star Trek version is intended to avoid disturbance of an alien species' natural development.
  4. Could it be that what we are detecting is not craft with outer-space beings aboard, but are robotic missions, or even some sort of holographic projection? Unless advanced civilizations have found a way to exceed the speed of light (extremely unlikely, if the cosmos behaves as we think it does), space travel between star systems would require hundreds of thousands of years, so sending live beings aboard a spacecraft would require an enormous amount of food and other life support systems to haul along.
  5. Might the visitors simply wish to observe us and to avoid contact? This possibility differs from the Prime Directive proposal (#3), in that technologically-advanced species have likely long ago solved the issue of aggression and war, in order to survive—if they ever had it. They may be shocked at how the human species mistreats itself and its environment and have decided to keep their distance, until we either do ourselves in or grow up and figure out how to get along and behave.


I'd like to think that this last point is what may be the most likely option. If those UFOs do happen to be from outer space and their technology is so superior, we would be no match for them, if they decided to attack. But might that possibility be just a projection of our violent tendencies onto them? Why should they be like us? Maybe they are peaceful  beings and are just waiting to see how we develop. After all, if they’ve invested all that time for space travel, they could afford to wait.


Sunday, January 2, 2022

Immaterial Mortality

 In 1905 Albert Einstein published his groundbreaking Special Theory of Relativity. I've written before about how revolutionary his ideas were. They solved a conundrum that had been bedeviling physicists for several years, regarding the properties of light. Whereas scientists had been considering time to be constant for all observers (regardless of their location or motion), the speed of light was seen as variable, being dependent on an observer's behavior. Einstein proved it to be the opposite. He began with the assumption that the velocity of light would be seen as identical for everyone—regardless of how fast they moved or where they were. The consequence of this premise is that the passage of time is a variable; the march of time depends on your speed... that is, while time is not a constant, the speed of light is.

One commonly-expressed result of his relativity theory is the so-called “Twin Paradox.” Calculations (later proved by measurements) showed that, if one twin takes off on a rocket ship and returns some time later, the traveling twin will be a tad younger than the twin who stayed home. This is very counterintuitive. Time for the traveling twin actually passes more slowly.


These relativistic effects are not usually seen until an object travels at a significant fraction of the speed of light, but it does show up for something that many people use every day: their smart phones, for locating themselves on the planet's surface. The GPS system must use relativistic calculations; otherwise your position would be tens of yards (or meters) in error. Your smart phone directions would have you driving into brick walls or into a lake. Well, sometimes that does happen, but the error can be mostly attributed to human inattentiveness.  


I have made some relativistic example calculations to illustrate the lapsed time for space ships of various speeds to travel to our nearest galaxy (Andromeda) and back.  Andromeda is about 2.5 million light years away. In other words, light would require 5 million years to travel to Andromeda and return... at least that's the elapsed time we observers back on Earth would measure. If time is relativistic, however, what would be the elapsed time for our space traveler at these different speeds? It would be less, according to Einstein; how much less would be a function of how fast the ship traveled. To illustrate this, I have shown the elapsed time in the table below for a spaceship at five different speeds.


Spaceship speed

 50,000 miles per hour

0.5c

0.9c

0.999c

C

Round trip time

35 billion years

4400 years

1260 years

120 years

Zero time


The first entry in the table is for a hypothetical spaceship whose speed is roughly comparable to today's spacecraft: it does the trip at 50,000 miles per hour (83,000 km per hour). To illustrate how slow this is, the trip would require some 35 billion years! Clearly, we must go faster.


For the second entry in the table, I assume a spaceship that can travel at half the speed of light (0.5C, where “c” is the scientific symbol used for light speed, which is 186,000 miles per second, or 300,000 km per second.) It will be a long time—if ever—before we'd reach that kind of speed. Nonetheless, for illustration purposes, the round trip to Andromeda would require 4,400 years for those aboard that ship, if they traveled at half the speed of light. That’s still a very long trip.


Let's say our imaginary ship could travel at 90% the speed of light (0.9c). Now the trip for those on board would be down to 1,260 years. Let's go even faster: to 99.9% the speed of light (0.999C). Then the trip could be finished in a mere 120 years.


For reasons I won't go into here, no real spacecraft could ever reach these speeds, despite the accomplishments of the starship USS Enterprise on “Star Trek,” which can reach warp speed eight—some eight times the speed of light! That's a fun way to fly around space, but is entirely fictional. Unfortunately, those interstellar distances will remain way beyond us mortals.


I've included one more interesting calculation in the table: the lapsed time to and from Andromeda Galaxy, for something that manages to travel right at the speed of light. (One of the consequences of Einstein's theory is that nothing can ever exceed the speed of light; it's an absolute upper bound.) For that light-speed trip, no time has passed at all! In fact, an object traveling at the speed of light can traverse the entire universe (and back, if it wishes) and never register any time lapse!


What kind of “thing” could travel at the speed of light? Well, light itself does, which we may describe as photons zinging along at c. Photons can do this only because they have no mass... they are completely immaterial. A consequence of  photons being massless is that they always are moving at the speed of light... they can exist only as moving particles.


So if you could ride along with a photon at the speed of light, you would in essence become immortal. Of course, your material being would never withstand the trip, but the massless photon can. So, for us material mortals back home, photons would require five million years for the round trip to Andromeda, but to them, they do it in no time at all.  That, it seems to me, is a definition of immortality.


As I pondered this fascinating result recently, it occurred to me that, while we material beings are mortal—often also described as being temporal, ephemeral, or perishable critters—some religions consider our souls to be immortal. If we do have a soul, it is immaterial; it is massless.


So a massless soul—like the massless photon—can only exist as something traveling at the speed of light. It could go on its merry way forever (that time lapse of “forever” being what we stationary mortals would measure), taking no time at all, from its perspective. Would that not be a definition of our soul being immortal?