It looks like it was an error in the timing system. The OPERA installation (and other labs around the world) have recreated the experiment, and none have recorded FTL speeds. Oh well. This is good science. Hypothesis, test, analyze, repeat. I would have loved to have seen FTL neutrinos, but I’ll take slow, measured progress. Onto the next great experiment.
The story of FTL neutrinos began when CERN reported that experiments measured neutrinos moving 60 nanoseconds quicker than light over a distance of 730 km between Geneva and Gran Sasso, Italy. People wondered if there was some error in the clocks, the GPS, or some calculation error. Although a few people were hoping for FTL neutrinos to be real, many people were simply waiting for an explanation of the error.
Well, it looks like the FTL measurement can be blamed on an “artefact of the measurement,” according to the latest press release from CERN. The ICARUS experiment at the Italian Gran Sasso laboratory re-ran the FTL neutrinos experiment. CERN reports that in this experiment, neutrinos did not travel FTL. Cue the sad trombone.
However, the latest press release from CERN does not explain specifically what kind of measurement error caused the FTL result. I expect more details to come, but for now, we remain under Einstein’s Law of Relativity. FTL starships will have to wait.
OK, that’s enough science. Back to March Madness! Go Hoyas!
As a brief recap, last September, Physicists had detected neutrinos travelling from the CERN laboratory in Geneva to the Gran Sasso laboratory near L’Aquila that appeared to travel FTL. According to the experiment, the neutrinos made the trip in about 60 nanoseconds less than light would take. This raised eyebrows because it seems to violate the results of many other experiments, not to mention, Albert Einstein and special relativity.
Yesterday, ScienceInsider reported that a faulty cable connection might be to blame for the 60 nanosecond discrepancy. Apparently, a fiber optic cable connecting the GPS receiver and the computer was bad. According to ScienceInsider’s source, once the connection was fixed, scientists determined how long it would take data to travel down the cable. According to the article? About 60 nanoseconds.
Phil Plait commented on this article at his Bad Astronomy blog. He notes that this story is unconfirmed, so he urges caution. Although he does find it amusing that of all the mechanical and technical errors that could have caused the experiment to report FTL neutrinos, he did not think “loose cable” would be on that list.
Ars Technica also commented on the report. Skim down to the bottom and their update. Apparently, Nature News received a statement from the researchers noting that they found two potential issues (the cable being one). It would appear that the two issues skew the data in opposite directions.
In other words, more data is needed. This means more experiments on FTL neutrinos. But what I don’t get is if the cable was loose, or the connection was bad, why would data arrive earlier than expected? Strange. Anyway, I remain skeptical that future experiments will confirm FTL neutrinos. My money is on some screw-up or less-than-precise measurement. But then again, if confirmed, FTL neutrinos would be very cool indeed.
I have written here and here about CERN reporting that it had measured neutrinos travelling faster than the speed of light (FTL), contradicting Einstein’s theory of special relativity. Today there is another update.
One of the criticisms levied at the experiment (and one cited as a possible error in their calculations) is that the scientists used a relatively long pulse of neutrinos (lasting 10 microseconds), making it difficult to measure exactly when the neutrinos arrived. CERN scientists re-ran the experiment using streams thousands of times shorter (3 nanoseconds) with long pauses (524 nanoseconds) between. The idea is that with longer pulses, it can be difficult to measure when individual neutrinos left one location and arrived at another. Therefore, these shorter bursts can remove some of that uncertainty and be measured more accurately.
As described here and here, the researchers new results were consistent with the original experiments. But as Phil Plait points out here, the new experiments used the same timing device. So although the measurements might be more precise, they may be off by the same amount (think of it as measuring something twice with a bad ruler–consistent, but nevertheless incorrect results). He also points out that we still need to see replication of the experiment by other researchers.
Now, just to be clear, this is NOT, I repeat NOT, confirmation that neutrinos can travel FTL. It is merely a test of one of several possible causes of error in the original experiment. Nevertheless, this is a fascinating example of the scientific method in progress. Watch this space though. I’ll be sure to keep you updated as more experiments are resulted.
Yesterday, I posted a story about the possibility that researchers at CERN may have recorded neutrinos moving faster than the speed of light. I was one of many people who were/are excited about the possibility of faster than light (FTL) travel not only because I’m a science fiction fan, but also because this is a truly revolutionary finding, if it is true. As in we’d have to redefine physics as we know it.
So now that everyone has had time to calm down and get a good night’s sleep, let’s take another look. To begin with, CERN’s findings are now online, ready to be examined by scientists around the world and replicated by other labs. This is just as they should be–this is good science.
So what are some possible explanations for CERN’s findings? One of my go-to places to check for information on such things is Phil Plait’s (@badastronomer) blog. Phil did not disappoint. His post summarizes things very nicely. First, he writes a bit about how neutrinos behave. In 1987, scientists were able to measure a supernova. Neutrinos arrived only hours before the light from the supernova–this is NOT because neturinos moved FTL, but because they are released almost immediately, while photons take longer to be ejected. But had the neutrinos been moving at the speeds measured by CERN, the neutrinos would have arrived years before the light. No such neutrinos were recorded. Second, Phil examines the various errors that might have occurred, such as measuring the distance actually traveled, the moment of the neutrinos creation, and GPS calibration errors.
But as Phil says, the folks at CERN are not amateurs. I would think they would have found measurement errors by now (or even the possibility of them). Nevertheless, I still think this is the most likely culprit. But a post by New Scientist (@newscientist) offers an even more intriguing solution: what if the neutrinos skipped between dimensions, effectively reducing the distance between the measured start and finish points? This would mean the speed of light is still a hard speed limit, but would kick off a host of experiments about multiple dimensions.
As I said above, the claim of FTL neutrinos is extraordinary. As such, it will require extraordinary evidence to back it up. Most likely, the neutrinos were not moving FTL, so keep your space suits packed away. Let’s sit back and wait for the data to be examined, crunched, and re-crunched. Let’s wait for the experiments to be replicated again and again.
But it’s ok to hope for a little sci fi magic too. Part of me still is.