[Animation] Travelling at the Speed of Light

[Somamech]

I watched this video depicting travelling at the speed of light within our known solar system last Friday at work whilst waiting for my friend to finish so we could go and hike some mountains over the weekend. 

What surprised myself when this theoretical speed is put into context is how bloody slow this would be if we could travel the speed of light.  I can see why good Scifi does not waste time with light speed travel, it's a but like Chemical Rockets... Cool and all but wont get us far in a hurry 

Riding Light

In our terrestrial view of things, the speed of light seems incredibly fast. But as soon as you view it against the vast distances of the universe, it's unfortunately very slow. This animation illustrates, in realtime, the journey of a photon of light emitted from the surface of the sun and traveling across a portion of the solar system, from a human perspective.
I've taken liberties with certain things like the alignment of planets and asteroids, as well as ignoring the laws of relativity concerning what a photon actually "sees" or how time is experienced at the speed of light, but overall I've kept the size and distances of all the objects as accurate as possible. I also decided to end the animation just past Jupiter as I wanted to keep the running length below an hour

Original Video Source on Vimeo HERE:



Youtube Rip:



Anyway hope you all enjoy it as much as I did

[rdunk]

Yes Somamech, in terms of interstellar distances, light-years do mean a measly 6 trillion miles travel per earth year. With our own little spot in space - our Milky Way Galaxy - it is supposedly is about 100,000 light years across, so even just moving around within our own galaxy is nowhere near reality for we people of Earth - at least as far as "public space science" is concerned.

This light-speed movie is pretty neat, as it does show us that "light speed" is actually slow in context of even the expanse of our own little solar system, which is "peanuts distance" in relation to interstellar/intergalactic distances. Even warp drive technology (or whatever that becomes) would still be challenging for intergalactic travel.

[zorgon]

That is the thing people tend to forget when talking about sending signals to Aliens or that the Aliens are monitoring us.

We invented radio in 1895  but it wasn't very powerful till around 1930-40  Radar came in in 1934–1939 Same for Radio Telescopes. Those early transmissions were not focused nor very powerful so would likely not even make it out of the solar system as anything other than noise

So the I Love Lucy show is barely out at 50 light years from earth. Any aliens living just beyond that are just now getting the WWII broadcasts

But even then  radio and TV travel along a wave that is modulated  (info waves on the carrier wave)  This modulation tends to fade rapidly over distance. I doubt Lucy would be watchable at 50 light years it would be so degraded

5 years ago they sent a group of messages to the Gliese 581 system...That system is 20.5 LY away  So it will take another 15 years to get there  and the site is already down LOL and that signal is a tight beam from the biggest dish at Arecibo, Puerto Rico

I wonder if they pointed it at the system or where the system will be in 20.5 years At the speeds of the planets in the galaxy  that would be a prime factor and a hell of a calculation based on 'best guess'

So unless ET is living withing 100 LY or is passing by the Earth  They don't know we are here...


Plan to broadcast messages to alien worlds leaves cosmologists worrying



A plan to beam powerful radio messages to possible alien civilisations on distant planets has caused consternation among some scientists who believe it could spell doom for humanity on Earth.

Leading figures behind the 50-year-old Search for Extraterrestrial Intelligence (Seti), which uses radio telescopes to listen passively for unnatural signals from space, have now proposed an "active" form of search known as Meti – Messages to Extraterrestrial Intelligence. These signals will be aimed at the parts of the galaxy where Earth-like planets and life may exist, based on the growing number of "exoplanets" beyond our solar system identified by the Kepler space telescope, which include many in the so-called "habitable zone" of a star.

However, critics say the proposal betrays the founding principles of Seti, which were about listening rather than transmitting. They fear that sending signals of our existence could lead to visits from malign extraterrestrials intent on doing harm to humans.

http://www.independent.co.uk/news/science/plan-to-broadcast-messages-to-alien-worlds-leaves-cosmologists-worrying-10042555.html

[space otter]

oh dear there are those  scientific words again   
science definitions makes certain assumptions

maybe we can make the assumption that all we think we know is a guess at best.
..no firm ground
oh my..
that could be scary tragic to some..
OR


it could put us in the realm of 

ANYTHING IS POSSIBLE..
we are not limited to scientific defintions

The SI definition makes certain assumptions about the laws of physics





Updated 2014 by Don Koks.  Original by Steve Carlip (1997) and Philip Gibbs 1996.




Is The Speed of Light Everywhere the Same?

The short answer is that it depends on who is doing the measuring: the speed of light is only guaranteed to have a value of 299,792,458 m/s in a vacuum when measured by someone situated right next to it.  But let's approach the question by considering its various meanings.


Does the speed of light change in air or water?

Yes.  Light is slowed down in transparent media such as air, water and glass.  The ratio by which it is slowed is called the refractive index of the medium and is usually greater than one.*  This was discovered by Jean Foucault in 1850.

When people talk about "the speed of light" in a general context, they usually mean the speed of light in a vacuum.  They also usually mean the speed as measured in an inertial frame.  This vacuum-inertial speed is denoted c.


Is c, the speed of light in a vacuum inertial frame, constant?

At the 1983 Conference Generale des Poids et Mesures, the following SI (Systeme International) definition of the metre was adopted:

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.

This defines the speed of light in vacuum to be exactly 299,792,458 m/s.  Unfortunately it doesn't mention anything about inertial frames, but you can consider a measurement in an inertial frame to be implied.

However, this is not the end of the matter.  The SI is based on very practical considerations.  Definitions are adopted according to the most accurately known measurement techniques of the day, and are constantly revised.  At the moment you can measure macroscopic distances most accurately by sending out laser light pulses and timing how long they take to travel using a very accurate atomic clock.  (The best atomic clocks are accurate to about one part in 1013.)  It therefore makes sense to define the metre unit in such a way as to minimise errors in such a measurement.

The SI definition makes certain assumptions about the laws of physics.  For example, it assumes that the particle of light, the photon, is massless.  If the photon had a small rest mass, the SI definition of the metre would become meaningless because the speed of light would change as a function of its wavelength.  The SI Committee could not just define it to be constant; instead, they would have to fix the definition of the metre by stating which colour of light was being used.  Experiments have shown that the mass of the photon must be very small if it is not zero (see the FAQ entry What is the mass of the photon?).  Any such possible photon rest mass is certainly too small to have any practical significance for the definition of the metre in the foreseeable future, but it cannot be shown to be exactly zero—even though currently accepted theories indicate that it is.  If the mass weren't zero, the speed of light would not be constant; but from a theoretical point of view we would then take c to be the upper limit of the speed of light in vacuum so that we can continue to ask whether c is constant.

The SI definition also assumes that measurements taken in different inertial frames will give the same results for light's speed.  This is actually a postulate of special relativity, discussed below.

Previously the metre and second have been defined in various different ways according to the measurement techniques of the time.  They could change again in the future.  If we look back to 1939, the second was defined as 1/86,400 of a mean solar day, and the metre as the distance between two scratches on a bar of platinum-iridium alloy held in France.  We now know that there are variations in the length of a mean solar day as measured by atomic clocks.  Standard time is adjusted by adding or subtracting a leap second from time to time.  There is also an overall slowing down of Earth's rotation by about 1/100,000 of a second per year due to tidal forces between Earth, Sun, and Moon.  There may have been even larger variations in the length or the metre standard caused by metal shrinkage.  The net result is that the value of the speed of light as measured in m/s was slowly changing at that time.  Obviously it would be more natural to attribute those changes to variations in the units of measurement than to changes in the speed of light itself, but by the same token it's nonsense to say that the speed of light is now constant just because the SI definitions of units define its numerical value to be constant.

But the SI definition highlights the point that we need first to be very clear about what we mean by constancy of the speed of light, before we answer our question.  We have to state what we are going to use as our standard ruler and our standard clock when we measure c.  In principle, we could get a very different answer using measurements based on laboratory experiments, from the one we get using astronomical observations.  (One of the first measurements of the speed of light was derived from observed changes in the timing of the eclipses of Jupiter's moons by Olaus Roemer in 1676.)  We could, for example, take the definitions of the units as they stood between 1967 and 1983.  Then, the metre was defined as 1,650,763.73 wavelengths of the reddish-orange light from a krypton-86 source, and the second was defined (then as now) as 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of caesium-133.  Unlike the previous definitions, these depend on absolute physical quantities which apply everywhere and at any time.  Can we tell if the speed of light is constant in those units?

The quantum theory of atoms tells us that these frequencies and wavelengths depend chiefly on the values of Planck's constant, the electronic charge, and the masses of the electron and nucleons, as well as on the speed of light.  By eliminating the dimensions of units from the parameters we can derive a few dimensionless quantities, such as the fine-structure constant and the electron-to-proton mass ratio.  These values are independent of the definition of the units, so it makes much more sense to ask whether these values change.  If they did change, it would not just be the speed of light which was affected.  All of chemistry depends on their values, and significant changes would alter the chemical and mechanical properties of all substances.  Furthermore, the speed of light itself would change by different amounts according to which definition of units was used.  In that case, it would make more sense to attribute the changes to variations in the charge on the electron or the particle masses than to changes in the speed of light.

In any case, there is good observational evidence to indicate that those parameters have not changed over most of the lifetime of the universe.  See the FAQ article Have physical constants changed with time?

(Note that the fine-structure constant does change with energy scale, but I am referring to the constancy of its low-energy limit.)


http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html

[rdunk]

With all of that said, what happens to the "Speed of Light" as it comes into contact with "dark matter"? Is it simply stopped by the dark matter, or is it just slowed down or diverted directionally. Is dark matter actually "matter", or is it "some sort of energized plasma"?

Since the Universe seems to be filled with dark matter, is it possible that the dark matter might hold the "key" to successful intergalactic travel. If we can know how it affects light-speed, then maybe we can begin to guess how the basic dark matter might affect "the Enterprise, if we send it out there!   What is the possibility of dark matter being the foundational element/provision for stargate access/worm-hole intergalactic passageways - - if so, then maybe we could somewhat forget about the limitations of mere light-speed, and really get serious about space travel!!!??

Just thoughts!

[zorgon]

Good question. If they say there is so much dark matter you would think we would see a lot of light blocked

[Somamech]

Well interesting thoughts all round!

After I posted this and went to bed I was thinking about the aspect of how people though either training or by "gift" can seemingly explain with some accuracy what occur's at distant locations which defy light speed.

It does make one wonder why so many labs are working on Quantum Entanglement huh ?

I recall this news regarding teleporting light from ANU being broadcast on Aussie news on a Saturday or Sunday years ago.  The crux of the story is that some scientist's at a National Uni in the Nation's heart made world news for teleporting a laser beam.

Australian teleport breakthrough

http://news.bbc.co.uk/2/hi/science/nature/2049048.stm

Quantum teleportation technique improved

http://www.newscientist.com/article/dn2419-quantum-teleportation-technique-improved.html#.VONME_7LdIU

Dark Matter is a funny thing huh when described via science.  Not picking on science at all as we all do what we do to our best and they do a great job, but I do wonder if what is called dark matter is merely what was known as "other realm's" to the adept back in the day and to this day too!