Ah, the fast-paced life of a theoretical physicist! I just got done giving a one-hour talk in Rome, given at a workshop for experts on the ATLAS experiment, one of the two general purpose experiments at the Large Hadron Collider [LHC]. Tomorrow morning I’ll be talking with a colleague at the Rutherford Appleton Lab in the U.K., an expert from CMS (the other general purpose experiment at the LHC). Then it’s off to San Francisco, where tomorrow (Wednesday, 5 p.m. Pacific Time, 8 p.m. Eastern), at the Exploratorium, I’ll be joined by Caltech’s Sean Carroll, who is an expert on cosmology and particle physics and whose book on the Higgs boson discovery just won a nice prize, and we’ll be discussing science with science writer Alan Boyle, as we did back in February. [You can click here to listen in to Wednesday’s event.] Next, on Thursday I’ll be at a meeting hosted in Stony Brook, on Long Island in New York State, discussing a Higgs-particle-related scientific project with theoretical physics colleagues as far flung as Hong Kong. On Friday I shall rest.
“How does he do it?”, you ask. Hey, a private jet is a wonderful thing! Simple, convenient, no waiting at the gate; I highly recommend it! However — I don’t own one. All I have is Skype, and other Skype-like software. My words will cross the globe, but my body won’t be going anywhere this week.
We should not take this kind of communication for granted! If the speed of light were 186,000 miles (300,000 kilometers) per hour, instead of 186,000 miles (300,000 kilometers) per second, ordinary life wouldn’t obviously change that much, but we simply couldn’t communicate internationally the way we do. It’s 4100 miles (6500 kilometers) across the earth’s surface to Rome; light takes about 0.02 seconds to travel that distance, so that’s the fastest anything can travel to make the trip. But if light traveled 186,000 miles per hour, then it would take over a minute for my words to reach Rome, making conversation completely impossible. A back-and-forth conversation would be difficult even between New York and Boston — for any signal to travel the 200 miles (300 kilometers) would require four seconds, so you’d be waiting for 8 seconds to hear the other person answer your questions. We’d have similar problems — slightly less severe — if the earth were as large as the sun. And someday, as we populate the solar system, we’ll actually have this problem.
So think about that next time you call or Skype or otherwise contact a distant friend or colleague, and you have a conversation just as though you were next door, despite your being separated half-way round the planet. It’s a small world (and a fast one) after all.
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@Matt:
Sorry to be off topic, but this story has been all over the news in the last few days. Juan Maldacena and Leonard Susskind proposed that black hole pairs could be linked by entanglement. Is there any chance you might do a future write-up on this to flesh out this idea for your readership?
http://www.csmonitor.com/Science/2013/1204/Spooky-physics-How-quantum-entanglement-could-link-wormholes
Brilliant article, though for better picture and sound quality I recommend Facetime. I talk to my parents practically everyday from London to a small town next to a desert in the subcontinent (more than 4000 miles away) and to see them in HD makes their day and mine 🙂 future is already here, thank you Physics and thank you technology 🙂
And unlike you sometime I do travel a lot across the globe, thankfully in the last five years it is easy to see and hear your loved ones wherever you are 🙂
One more issue. Query how much different the speed of signals in modern international telecommunications equipment like wires and fiber optic equipment due to slower speeds of signals in these mediums than light in a vacuum and due to non-straight paths from point to point, differs from the speed of light. This is still observably better than the speed of light trip from the surface to a communication satellite and back the the surface not through wires or fiber optic or switching in nearly straight lines with satellite phones, so it can’t be that much of a degregation, but is it 1% less than the speed of light, 5%, 10% or 50%?
The speed of electricity in unshielded copper wire is 3%-5% worse than the speed of light, (coax cable used by cable modems is about 34% less than the speed of light) but fiber optic makes up a lot of the main connection routes and is similar or better than copper wire in this regard but still not speed of light in a vacuum. Also, there are indirect paths (perhaps as much as a third worse than a straight path), and there are switching/intermediate booster equipment delays too (fewer in fiber optic systems than copper wire systems).
In practice, Skype, etc. may be operating at something closer to 80,000-,140,000 as the crow flies miles per second, rather than 186,000.
A scenario in which a few seconds have to elapse between asking a question and transmitting a response sounds like a blessing to my ears and recalls the days well into the 19th century when businesses in urban centers received several mail deliveries per day and a correspondence of six or eight letters might be exchanged in a single day (you actually see these quoted in old court cases) much as we do by text message and e-mail now.
This is to my mind quite a bit more civilized than telephone communications and Skype where someone can presume to impose upon you whenever they choose to communicate with you whether you are inclined to interrupt whatever you are in the middle of doing or not.
This is also as good of a place to note that high speed long distance communication actually dates back to at least as far as the Bronze Age. The concept is familiar to Lord of the Rings movie fans – where a network of bonfires on hills are lit to give notice to the next station down ten to thirty miles down the road who then pass on the message which as a pre-agreed meaning. In England, this system of hill forts and cleared sight lines was the original purpose for which England’s Ley Lines were constructed. A similar system is historically attested in China where the “Never Cry Wolf” fable involves a princess who sounded the alarm with that system one time to many. Native Americans in parts of the U.S. used “smoke signals” in a similar way. Done well, such a system can send messages at about 30 miles per minute (1800 miles per hour), which while not even 186,000 miles per hour, is still quite competitive with any form of courier (even by modern supersonic planes).
Yes, on Earth the speed of light is effectively infinite. But out there – out among the stars – it is pathetically slow. You may all accept it, and many of you embrace it, but I refuse. I know about the countless experiments that verify c as the ultimate speed limit – and still I refuse…
Somewhere, somehow – right now – a starship executes an impossible turn and then accelerates at 1000g (while its occupants only experience ~1g). In less than a day the ship blows through the ‘ultimate speed limit’ of 20th Century physics, leaving it far behind…
Amidst the great din you wonder at the eerie silence – not realizing it is by carrier pigeon – not carrier wave – that the commerce and communication of the heavens precedes.
“Ah Dino, you silly dreamer, you have no proof.” You are right, in this matter, only faith…
If the speed of light were much smaller – wouldn´t this slow down everything, including chemistry, the speed of our thoughts in our brains, the speed with which we talk, and the speed at which our body ages? If everything were slowed down, maybe we even don´t experience a difference – waiting more time for an answer is no problem if we live longer and think slower?
Well, this is just a first idea, maybe not “everything” were slowed down by a smaller speed of light but certainly not only the way we communicate via skype and TV would be affected, so it would be an interesting thought experiment to imagine such a world.
Yes, puzzling isn’t it? Speed of light is constant and the universe is expanding, so what is happening to time? Is time changing or is it constant too? Schrodinger’s time is not really a parameter but the time in the uncertainty principle is, i.e. the time interval it takes for a quantum change of state. Is this interval changing or is it constant? If it was changing would that explain perturbation and hence symmetry breaking?
Time is merely a mathematical quantity (numerical order) of material change. In physical world, time is exclusively a mathematical quantity. In this sense mathematic is a part of physical universe. Temporal experience of material change “one after other in time” is result of neuronal activity of the brain. Imaginary numbers show up in space-time intervals when space and time separations are combined at near the speed of light, and spatial separations are small relative to time intervals.
“Time dilation” is a physical reality because, of the speed at which our body ages and the speed of light is constant – so “rest mass” is a relative order ?
Thanking Mr.Oaktree and Mr.S.Dino and I repeat their opinions.
Professor Strassler has a jet on his own or not, his good soul worth billion $ – for providing platform.
7PM in what time zone?
Yes physics is all about the transfer and measurement of information.
I mean by interacting with your peers and colleagues you are no different from the interactions of particles of matter you study. It seems that information is the universal currency. Its circulation and amplification animates nature. One generation ( of particles, animals plants etc )transfers information to the next. In society, the gathering of information (knowlege) and its exchange generates wealth.Yes Matt, with the vast wealth of knowlege you have gained you are indeed leaving a glamourous lifestyle.
Twenty years ago, long before Skype, E.O. Wilson and I were interviewed by Charles Osgood on the Osgood files on the subject of Wilson’s concept of Biophilia-he in Boston and I in Sacramento, CA. Radio waves broadcasted the interview around the globe. I did not meet Wilson for another ten years face to face, but our ideas met because of the speed of electromagnetic radition. AWESOME!!