FTL astronomy

[gmPhil]

A slightly silly question, maybe, but... If light/information was transmitted instantaneously, how different would the night sky look? e.g, would the Big Dipper still look like it does to us, or would it be a different "shape"? Presumably some stars known to be near the end of their life would no longer show at all.... Has anyone compiled a picture of the night sky under such conditions? This would (in a sense) represent the stars and other objects as they are in relation to us right now, rather than as they were X light years ago when the light from them left them.

[Chris Peterson]

A slightly silly question, maybe, but... If light/information was transmitted instantaneously, how different would the night sky look? e.g, would the Big Dipper still look like it does to us, or would it be a different "shape"? Presumably some stars known to be near the end of their life would no longer show at all.... Has anyone compiled a picture of the night sky under such conditions? This would (in a sense) represent the stars and other objects as they are in relation to us right now, rather than as they were X light years ago when the light from them left them.

It wouldn't look all that different. Virtually all the bright stars are less than 1000 ly away, and all the visual stars no more than a few thousand ly. That means those stars are still around, and would not have moved much.

I think that answers what you were really asking, but in fact, if there was no limit on the speed of light, you'd introduce some secondary effects. One of those is that the resolution of Olber's Paradox changes. While you still have a loss of total energy to redshift, you would now receive energy from many more stars (perhaps an infinite number). I'm not sure how that would impact the night sky. Also, you would simultaneously see all the supernova present in a volume of space millions of ly across, so there would probably be many additional bright stars in the night sky.

The telescopic sky would be very different, of course.

[neufer]

[b][color=#0000FF]A harmonically oscillating electric dipole produces a total time-average radiated power P given by [img]http://upload.wikimedia.org/math/5/9/8/598425e64f7db03a080db9f59f5a57c3.png[/img][/color][/b]

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If there was no limit on the speed of light, you'd introduce some secondary effects.

If there was no limit on the speed of light,
you'd introduce one very large primary effect:

All wavelengths would be infinitely long

Transmitters & receivers would also have to be infinitely long
in order to effectively transmit & receive; ...hence,
there would be no radiation emitted or detected period.

[Chris Peterson]

If there was no limit on the speed of light,
you'd introduce one very large primary effect:

All wavelengths would be infinitely long

And, of course, there would be a multitude of other major effects, given the prevalence of c as an element in the value of major constants, as well as an element in many fundamental theories. Basically, the Universe as we know it would fall apart completely if the value of c were to change significantly. Which is why the only realistic way to interpret the original question is "what would the sky look like if we could see objects where they are now, as opposed to where they were when they emitted their light".

It is interesting to consider the appearance of the Universe if the speed of light were infinite, but c was unchanged, however.

[bystander]

Light hits near infinite speed in silver-coated glass
New Scientist | Jeff Hecht | 2013 Jan 07

[i]Blink and you'll miss it, a million times over [b](Image: John Renstenzefa/Superstock)[/b][/i]

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A nano-sized bar of glass encased in silver allows visible light to pass through at near infinite speed. The technique may spur advances in optical computing.

Metamaterials are synthetic materials with properties not found in nature. Metal and glass have been combined in previous metamaterials to bend light backwards or to make invisibility cloaks. These materials achieve their bizarre effects by manipulating the refractive index, a measure of how much a substance alters light's course and speed.

In a vacuum the refractive index is 1, and the speed of light cannot break Einstein's universal limit of 300,000 kilometres per second. Normal materials have positive indexes, and they transmit at the speed of light in a vacuum divided by their refractive index. Ordinary glass, for instance, has an index of about 1.5, so light moves through it at about 200,000 kilometres per second.

No threat to Einstein

The new material contains a nano-scale structure that guides light waves through the metal-coated glass. It is the first with a refractive index below 0.1, which means that light passes through it at almost infinite speed, says Albert Polman at the FOM Institute AMOLF in Amsterdam, the Netherlands. But the speed of light has not, technically, been broken. The wave is moving quickly, but its "group velocity" – the speed at which information is travelling – is near zero.

As a feat of pure research, Polman's group did a great job in demonstrating the exotic features of low-index materials, says Wenshan Cai of the Georgia Institute of Technology, who was not involved in the work.

Practical applications might also be in the offing. The metal component that reduces the refractive index also increases absorption, so the light can't travel far, says Polman. Still, the material could be used to transmit light rapidly over the very short distances in optical integrated circuits, he says.

Experimental Verification of n=0 Structures for Visible Light - Ernst Jan R. Vesseur et al

• Physical Review Letters 110(1) 013902 (02 Jan 2013) DOI: 10.1103/PhysRevLett.110.013902

[neufer]

If there was no limit on the speed of light,
you'd introduce one very large primary effect:

All wavelengths would be infinitely long

And, of course, there would be a multitude of other major effects, given the prevalence of c as an element in the value of major constants, as well as an element in many fundamental theories. Basically, the Universe as we know it would fall apart completely if the value of c were to change significantly.

Certainly a Big Bang Universe would never be able to cool off without radiation.

However, I would think that non-relativistic quantum mechanics would work fine in a steady state universe.

Atoms, molecules, dust, planets, "black" dwarfs & neutron stars should all get along fine without radiation (or magnetic fields), IMO.

[Chris Peterson]

Certainly a Big Bang Universe would never be able to cool off without radiation.

However, I would think that non-relativistic quantum mechanics would work fine in a steady state universe.

Atoms, molecules, dust, planets, "black" dwarfs & neutron stars should all get along fine without radiation (or magnetic fields), IMO.

Perhaps. I wasn't really referring to a universe without radiation, but commenting on how many other constants and theoretical equations depend upon c being a finite constant. What would happen to the rest mass of an electron? What about energy-mass equivalence? I think all of quantum mechanics, relativity, and subatomic physics would fall apart if c were infinite. That's why I proposed allowing the speed of light to be infinite, but not c. I think that would be a better fit to your radiationless universe.

[neufer]

Certainly a Big Bang Universe would never be able to cool off without radiation.

However, I would think that non-relativistic quantum mechanics would work fine in a steady state universe.

Atoms, molecules, dust, planets, "black" dwarfs & neutron stars should all get along fine without radiation (or magnetic fields), IMO.

Perhaps. I wasn't really referring to a universe without radiation, but commenting on how many other constants and theoretical equations depend upon c being a finite constant.

The most noticeable such constant: the fine structure constant ~ 1/137 => 0.000

The world gets along just fine with a small fine structure constant;
having a zero small fine structure constant would make little difference.

(The world got along just fine for a quite long time under the assumption that it was flat.)

What would happen to the rest mass of an electron?

The mass would be a mysterious text book number that one couldn't calculate theoretically... just as it is today.

What about energy-mass equivalence?

Rest masses mc² would be infinite but unmeasurable.

Measurable Kinetic Energies would remain much the same:
K.E. = mv²/2 + negligible terms = mc² * (v²/2c² + negligible terms)

There would probably be nuclear phlogiston theorists suggesting that the exothermic heat released by a nuclear reaction would make the nuclear waste weigh somewhat less than before... but experiment would soon prove those nuclear phlogiston theorists wrong.

I think all of quantum mechanics, relativity, and subatomic physics would fall apart if c were infinite. That's why I proposed allowing the speed of light to be infinite, but not c. I think that would be a better fit to your radiationless universe.

I don't know how to speculate about a universe where light would effectively be a tachyon.

However, much of the universe gets along very well non-relativistically (almost as if c were infinite).

Nevertheless, in the limit of infinite c there could be no radiation
and hence no APOD (such that our universe would fall apart).

[Beyond]

Hmm... if the light of the universe was only tachyon, the Romulans couldn't hide in their cloaked ships. But... would there be any Romulans in the first place? Or... even any Humans

[neufer]

Hmm... if the light of the universe was only tachyon, the Romulans couldn't hide in their cloaked ships. But... would there be any Romulans in the first place? Or... even any Humans

• Or... even any Reptilians

Click to play embedded YouTube video.

<<David Vaughan Icke (pronunciation: IKE, born 29 April 1952) is a British writer and public speaker, known for his conspiracy literature. At the heart of his theories lies the idea that a secret group of reptilian humanoids called the Babylonian Brotherhood controls humanity, and that many prominent figures are reptilian, including George W. Bush, Queen Elizabeth II, Kris Kristofferson, and Boxcar Willie.

Icke introduced the reptoid hypothesis in The Biggest Secret (1999), which identified the Brotherhood as descendants of reptilians from the constellation Draco, who walk on two legs and appear human, and who live in tunnels and caverns inside the earth. He argues that the reptilians are the race of gods known as the Anunnaki in the Babylonian creation myth, Enûma Eliš. Icke argues that they came specifically for "monoatomic gold," a mineral he says can increase the carrying capacity of the nervous system ten thousandfold. After ingesting it, the reptilians can process vast amounts of information, speed up trans-dimensional travel, and shapeshift from reptilian to human form. They use human fear, guilt, and aggression as energy. Lewis and Kahn argue that Icke is using allegory to depict the alien, and alienating, nature of global capitalism.

Icke writes that the Anunnaki have crossbred with human beings, the breeding lines chosen for political reasons, arguing that they are the Watchers, the fallen angels, or "Grigori," who mated with human women in the Biblical apocrypha. Their first reptilian-human hybrid, possibly Adam, was created 200,000–300,000 years ago. There was a second breeding program 30,000 years ago, and a third 7,000 years ago. It is the half-bloods of the third breeding program who today control the world, more Anunnaki than human, he writes. They have a powerful, hypnotic stare, the origin of the phrase to "give someone the evil eye, " and their hybrid DNA allows them to shapeshift when they consume human blood. Richard Kahn and Tyson Lewis argue that the reptilian hypothesis may simply be Swiftian satire, a way of giving ordinary people a narrative with which to question what they see around them.>>

[Beyond]

Uh-oh, the smilie you used for the evil-eye, neufer, may cause you to be hearing clicking sounds from someone's clicking sharp pointy things together, in antisipation of...

[saturno2]

This value c is a constant. Is the speed of light in vacuum
300,000 km/sec.
This velicity c can not to be infinite, because to do so would need to have a positive acceleration.
And for this, the photons need extra energy for increase the velocity. It is not possible. ( In the Universe )
You can increase the speed c in particle accelerators or by passing light through
of special materials. But for short distances.

[Chris Peterson]

You can increase the speed c in particle accelerators or by passing light through
of special materials. But for short distances.

You can change the speed of light, but you can't change c, which is a universal constant.

[Markus Schwarz]

The most noticeable such constant: the fine structure constant ~ 1/137 => 0.000

The world gets along just fine with a small fine structure constant;
having a zero small fine structure constant would make little difference.

Having a vanishing fine structure constant means that there would be no electric charge. Thus, it would make a big difference compared to the world as we know it.

[neufer]

The most noticeable such constant: the fine structure constant ~ 1/137 => 0.000

The world gets along just fine with a small fine structure constant;
having a zero small fine structure constant would make little difference.

Having a vanishing fine structure constant means that there would be no electric charge.
Thus, it would make a big difference compared to the world as we know it.

Having a vanishing fine structure constant means that
"there would be no electromagnetic interaction."

There would still be an electric field but there would be no magnetic field
(because a magnetic field is simply a relativistic effect of the electric field).

(There would also probably be no Sommerfeld ... or summers, for that matter.)

<<In physics, the fine-structure constant (usually denoted α) is a fundamental physical constant,
namely the coupling constant characterizing the strength of the electromagnetic interaction.

Being a dimensionless quantity, it has constant numerical value in all systems of units.

Arnold Sommerfeld introduced the fine-structure constant in 1916.

The current recommended value of is 1/137.035999074(44).>>

(A value of zero is NOT recommended )

[neufer]

You can change the speed of light, but you can't change c, which is a universal constant.

• A forward slash or vertical line will often suffice: c ¢

[makc]

Nice observation about c being constant, what's more important is meter definition relying on it as per SI 2.1.1.1 so we would no longer have our current way to measure distance if c became infinite. Well, we could go back to iron stick meter prototype and Michelson-Morley experiments.