Thought experiments
 

Let us assume that the speed of neutrinos travelling through a significant chunk of Europe is indeed greater than the speed of light [i]in vacuo[/i]. What would be the consequences of these two possible reasons?

1) The measured speed of the neutrinos is indeed the maximum speed of information transfer and that light travels at less than that speed. In other words, Einstein had the right idea, he just mis-identified the correct signalling mechanism.

2) The matter lying within the path of the neutrino beam has a refractive index for neutrinos which is less than unity.

How does known observational and experimental information distinguish between the possibilities and/or rule them out?

One obvious (to me) mark against the first proposal is that a pulse of antineutrinos was detected at a couple of facilities at close to the same time as the electromagnetic pulse from SN1987a. That supernova was sufficiently far away for the time discrepancy to be very signficant indeed --- on the order of years --- if the first explanation is correct. OTOH, the timing measurement is inherently imprecise enough for the second proposal to be consistent with observation. A supernova collapse takes of the order of seconds for the neutrinos to be released and days for the light. The refractive index of the earth would be so close to unity that the neutrino pulse would arrive only nanoseconds early.

I'm sure there must be other consequences which can be detected with modern technology.


Paul

[QUOTE=cheesehead;273646]Beside that article is a link to this one:

[B]The 'first true scientist'[/B]

[URL]http://news.bbc.co.uk/2/hi/science/nature/7810846.stm[/URL]

al-Hassan Ibn al-Haytham

Our science and mathematics texts need to include more credit for the achievements of "the period between the 9th and 13th Centuries [that] marked the Golden Age of Arabic science."[/QUOTE]

The article about the "first true scientist" completely ignores all the scientific achievements made by the Chinese many centuries before the period discussed. Seismographs, compasses, water-driven armillary spheres, gunpowder, crossbows, hot air balloons, schools of logic and method.

I realize that the article is intended to remind Westerners about the early scientific achievements of the Arabic world, and agree that we should give more credit there, but it goes too far to label someone of that time period as "the first true scientist" when they were centuries behind these other achievements.

Norm

[QUOTE=Spherical Cow;275001]The article about the "first true scientist" completely ignores all the scientific achievements[/QUOTE]There's a difference between science and technology.

[quote]made by the Chinese many centuries before the period discussed. Seismographs, compasses, water-driven armillary spheres, gunpowder, crossbows, hot air balloons, [/quote]... each of which is a technological achievement. I don't see scientific achievements, such as a theory of how and why seismographs or compasses or gunpowder worked, in that list. Did they document an understanding of the scientific principles involved in hot-air ballooning?

Did they make other inventions that used the same scientific principles in a different context, such as using rockets for scientific investigation of the atmosphere (e.g., watching what happened to the smoke trails at high altitudes) instead of just fireworks?

[quote]schools of logic and method.[/quote]Did those schools incorporate all the hallmarks of the [I]modern scientific method[/I]?

The BBC article describes that as:

the approach to investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge, based on the gathering of data through observation and measurement, followed by the formulation and testing of hypotheses to explain the data.

Did the Chinese indeed formulate and test hypotheses in a systematic manner, as Ibn al-Haytham did? Did their schools of logic and method teach an abstract method for science comparable to the modern one?

As Richard Feynman pointed out, science is the best way we have to avoid fooling ourselves. How did the Chinese systematically and consciously avoid fooling themselves about what they thought they knew?

[url]http://ca.news.yahoo.com/cyclops-shark-other-cryptic-creatures-october-creepy-113008213.html[/url]

I always wondered why it had that queer tilt.
[URL="http://dvice.com/archives/2011/10/we-now-know-why.php"]Uranus takes a pounding more frequently than thought.[/URL]

[QUOTE=Uncwilly;275317]I always wondered why it had that queer tilt.
[URL="http://dvice.com/archives/2011/10/we-now-know-why.php"]Uranus takes a pounding more frequently than thought.[/URL][/QUOTE]

Mine? No, for sure. Maybe yours....:smile:

There's another way to tilt the planet:

Suppose, for a minute, that it hasn't always orbited the sun, but is an acquisition in an encounter with another star?

[QUOTE=Christenson;275333]There's another way to tilt the planet:

Suppose, for a minute, that it hasn't always orbited the sun, but is an acquisition in an encounter with another star?[/QUOTE]What effects on the other planets in the solar system would you expect from such an encounter?

Paul

Besides heavily elliptical orbits not in the plane of the ecliptic? A massive biological disaster as climate conditions on a planet with life changed drastically? Maybe a planet or two in no orbit at all?

I'm also wondering how long it would take using tidal effects to re-align the spin of a planet such as neptune from 3/4 of the way to 90 degrees to 1/4 the way to 90 degrees.

Article: If German Satellite Falls on Your House, Who Pays for Repairs?
 

[URL]http://www.lifeslittlemysteries.com/falling-satellite-rosat-damage-liability-2109/[/URL]

Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany's space agency, now predicts that its ROentgen SATellite (ROSAT) X-Ray observatory will deorbit sometime between Friday, October 21 and Monday, October 24. Much of the X-ray satellite will burn up in the atmosphere, although 30 pieces are expected to survive reentry.

☄☄☄☄The largest single fragment could weigh up to 1.7 tons.☄☄☄☄

Aerospace engineers from Analytical Graphics, Inc. (AGI) used the company's analysis and visualization software to create this video depicting:
• ROSAT in its current orbit
• The satellite's ground track
• Its burn-up in reentry

Although it is too early to predict the time and location of the reentry, DLR says that predictions of the time period will become more refined as the date of reentry draws nearer. As DLR's ROSAT satellite nears reentry, go to DLR (hyperlink to [URL]http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10432/620_read-830/[/URL]) to get the most current updates.

(Caption) Aerospace engineers from Analytical Graphics, Inc. (AGI) used the company's analysis and visualization software to create this video depicting ROSAT in its current orbit and during burn-up in reentry.
[url]http://www.youtube.com/watch?v=yezo3SMoPN8&feature=player_embedded[/url]

Re. FTL neutrinos
 

For those in the UK only, I believe:
[URL="http://www.bbc.co.uk/iplayer/episode/b016bys2/Faster_Than_the_Speed_of_Light/"]http://www.bbc.co.uk/iplayer/episode/b016bys2/Faster_Than_the_Speed_of_Light/[/URL]

Favourite bit:
The barman says, "Sorry we don't serve neutrinos".
A neutrino walks into a pub.