Boys and Girls! You too can make something travel faster than light!

Can't say I had realised this before, but physicist Bee has a fascinating post that starts:

If you sweep a laser pointer across the moon, will the spot move faster than the speed of light? Every physics major encounters this question at some point, and the answer is yes, it will. If you sweep the laser pointer it in an arc, the velocity of the spot increases with the distance to the surface you point at. On Earth, you only have to rotate the laser in a full arc within a few seconds, then it will move faster than the speed of light on the moon!

Now a bit more explanation:

This faster-than-light motion is not in conflict with special relativity because the continuous movement of the spot is an illusion. What actually moves are the photons in the laser beam, and they move at the always same speed of light. But different photons illuminate different parts of the surface in a pattern synchronized by the photon’s collective origin, which appears like a continuous movement that can happen at arbitrary speed. It isn’t possible in this way to exchange information faster than the speed of light because information can only be sent from the source to the surface, not between the illuminated parts on the surface. 

Oh, and your average laser pointer won't still be visible on the moon, and I have my doubts a laser strong enough to be visible is available from scientific supplies shops.

But, it's still fascinating.

(And it's posts like this that I sometimes re-read years later and think "Geez, I do run a great blog!")

Sort of disappointing

Search for advanced civilizations beyond Earth finds nothing obvious in 100,000 galaxies

From the link:

"Whether an advanced spacefaring civilization uses the large amounts of energy from its
galaxy's stars to power computers, space flight, communication, or something we can't yet imagine, fundamental thermodynamics tells us that this energy must be radiated away as heat in the mid-infrared wavelengths," Wright said. "This same basic physics causes your computer to radiate heat while it is turned on."

Theoretical physicist Freeman Dyson proposed in the 1960s that advanced alien civilizations
beyond Earth could be detected by the telltale evidence of their mid-infrared emissions. It was not until space-based telescopes like the WISE satellite that it became possible to make sensitive measurements of this radiation emitted by objects in space.

Roger Griffith, a postbaccalaureate researcher at Penn State and the lead author of the paper, scoured almost the entire catalog of the WISE satellite's detections—nearly 100 million entries—for objects consistent with galaxies emitting too much mid-infrared radiation. He then individually examined  and categorized around 100,000 of the most promising galaxy images.
Wright reports, "We found about 50 galaxies that have unusually high levels of mid-infrared radiation. Our follow-up studies of those galaxies may reveal if the origin of their radiation results from natural astronomical processes, or if it could indicate the presence of a highly advanced civilization."

In any case, Wright said, the team's non-detection of any obvious alien-filled galaxies is an interesting and new scientific result. "Our results mean that, out of the 100,000 galaxies that WISE could see in sufficient detail, none of them is widely populated by an alien civilization using most of the starlight in its galaxy for its own purposes. That's interesting because these galaxies are billions of years old, which should have been plenty of time for them to have beenlled with alien civilizations, if they exist. Either they don't exist, or they don't yet use enough energy for us to recognize them," Wright said.

AI and "catastrophic forgetting"

​Teaching a Computer Not to Forget — The Atlantic

Interesting.  

A glowing recommendation (heh)

Fukushima bottled water wins Gold Quality Award in Monde Selection ‹ Japan Today: Japan News and Discussion

Irvine on company tax (and the problem with economics)

Why Joe Hockey's tax review should focus on lowering company tax

Since returning to Fairfax, Jessica has been doing a pretty good job with explaining some economic issues.

The problem with economics (and I'd be sure this is not an original thought) is that there is "always something else going on" which makes pinning down cause and effect of particular policy settings very hard to work out.  And it enables economists from opposite and set ideological positions to look at the same set of global evidence and both claim they are vindicated.

Hence, with company tax, you can complain that the Australia rate is now uncompetitive, yet the American rate is even worse (and there appears little prospect of it dropping soon), but America is still achieving an economic recovery.  "Sure" the anti tax, small government economists will say "but if you look at countries X, Y and Z and their growth, consider how much faster the American recovery could have been!"  (And, of course, you can often look at some aspect of how country X, Y and Z operates which the ideologically committed would disagree with, so it's virtually impossible to find a country that you could say is a perfect example of following one consistent economic ideological line.)

I'm not saying that is impossible to ever get to a "truth" in economics; just that the very nature of it means that there are always going to ways for dubious economists to convince politicians that they are the ones who are right.

As with the world of moral philosophy, it pays to not tie oneself to any one analyst, and let intelligent common sense from outside the field guide your actions.

UFOs and Poltergeists

J. Allen Hynek Writes Letter About Infamous Ghost Experiment - The Black Vault Case Files

Ooh.

J. Allen Hynek wrote very sensible books in a measured tone about UFOs at the peak of public interest in them, and ended up being a consultant to Spielberg for Close Encounters (as well as making a cameo appearance.)  


Interestingly, the letter at his link shows that, despite his reputation for leaning towards the "alien spaceship"  side of likely explanations for UFOs, he did have an interest in the possible interconnection between psychic phenomena, including ghosts and poltergeists, and UFO sightings.

I wonder whether it was conversations with him that got Spielberg interested in writing the story for Poltergeist.  I guess the answer to this might be in a biography of Spielberg on my shelf that I've never got around to reading.

Speaking of the very enjoyable Poltergeist, the remake is due out soon.  The first trailer left me a bit underwhelmed, but the second one that came out recently is making me much more inclined to see it.  It is, I think, a great example of a scary movie trailer, particularly when you consider most viewers probably know the story.

Watch it in a dark room with headphones on, and see if doesn't cause a jump or two:

Catallaxy propaganda

Sinclair Davidson is back to his long standing favourite line of arguing that because the Australian government's tax revenue (when looked at as a simple dollar figure) has, after a post GFC dip, continued to climb since the Howard government, this actually means there is no "revenue problem" but only a spending problem.

Funny how he doesn't mention either population growth (21,542,000 in September 2008, and 23,581,000 in September 2014 - close enough to a 9.5% increase).  Or the growth in GDP.   (Not sure if inflation has been factored in; maybe it has?)

In short - of course revenue should have grown over the period in dollar terms; the question is whether it is growing at expected rates to cover expected needs of a growing, aging population.  To dwell on the rise without context is just ideological propaganda.

And as for arguments about what government is better at covering rather than private enterprise:  the recent DeLong/Krugman writings about it are of great interest.

Update:   I see Andrew Bolt continues his gullible following of any argument Catallaxy runs and re-posts the Davidson graph and line.

Corporate tax considered

Of course, if the "small government at any cost" crowd at the IPA (and ideological anti-taxers like David Leyonhjelm) think that corporate tax per se is a bad idea,  it's a safe assumption that it's actually a good idea.   But seeing they are being given a bit of media space to run their arguments, I've been looking for some pro-corporate tax articles on the net, and here is what I've found so far:

*  10 Reasons we Should Tax Corporations

*  Why corporate taxes are good for you

*  Why we need the corporate tax income tax

The IPAers end their article as follows:

But even if the government wishes to keep the corporate tax fiscal illusion going, there's hope. For all the handwringing about the double Irish Dutch sandwich, one point often missed is that Ireland has been very clever. That country's low corporate tax rates have brought in multinationals, and with them jobs and investment.

It's not obvious those low rates have come at a cost to the Irish budget. Corporate tax revenue as a percentage of total revenue in Ireland is almost exactly the OECD average. There's no reason we couldn't copy the Irish example – get in on the Irish-Dutch sandwich ourselves. The Irish make their own luck. So should we.

 Of course, some countries can do well out of the race to the bottom, by being first to get there.  And they win at a real, impoverishing, cost to other nations who recover diminishing revenue from economic activity in their country.

But people with a moral sense above that of Scrooge McDuck  can see that you can't expect all countries to succeed in this race.   There's only so many multinationals minimising tax to go around...

Style consultant needed

Seriously, Noel Pearson is in the Australian this morning looking like he slept in that suit, and is taking his fashion tips from childhood memories of Homocide Homicide. 

(Or perhaps I should just stop reading Benjamin Law.  Then I might even stop spelling Homicide as Homocide.)

Too generous

Why Hockey will have to clean up Costello's superannuation mess in May budget

It's hard not to be convinced by Peter Martin's explanation here.  

Lincoln death details

After the Assassination: Images from HBO's Living With Lincoln Documentary - The Atlantic

A great article here with some fascinating photos and details about  Lincoln's death and aftermath.


I can't say I've heard of this before, for example:

After performing the inquest into Lincoln's death, U.S. Surgeon General Joseph Barnes cut off a lock of the dead president's hair and gave it to one of Lincoln's servants, a man named Thomas Pendel. Pendel, who became Lincoln's chief  doorkeeper in 1864, was noted for his striking resemblance to Lincoln: The doorman's lanky frame nearly matched the president's odd dimensions and his facial features were so uncommonly similar to Lincoln's that Pendel was sometimes mistaken for the president himself.

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Related Story

John Wilkes Booth and the Higher Law

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It was this uncanny similarity that initially endeared the doorkeeper to Lincoln's son Tad. And it was Pendel who was ultimately left to comfort Tad after news of the president's death reached the family home and Lincoln's son came running to his father's lookalike, screaming, "Oh Tom Pen! Tom Pen! They have killed papa dead. They killed papa dead."

Later that May, Mary Todd asked the servant to put on her husband's black broadcloth coat and model his presidential office suit in a posthumous portrait painted by the famed Boston-based artist William Morris Hunt.

Though Pendel was later described as a "simple, uneducated" man, his possession of this snippet of hair, cut from the head of his dead presidential doppelgänger, along with the
elegant broadcloth, made him a person of particular interest for Lincoln's archivists.

 If this had happened today, there would be an online community of Lincoln assassination conspiracists who have the real Lincoln living in Argentina, and 25% of the population would believe it.  

The fattening

I mentioned my BMI last week, which I checked using a calculator on the Australian Heart Foundation website.

Using sliders to adjust weight and height, it's also accompanied by a graphic of a body that grows fatter as BMI increases.  The trouble is, it might have a bit of a problem with the gradation.

Here it is at a BMI of 25 which, at this morning's DNW (dry nude weight, a term of my invention with which I dismay female workers at the office), I have achieved, the illustration is this:

Yes, I can live with that image - seems pretty accurate to what I'm seeing in the mirror.




But move the weight scale up 1 kg, and at a BMI of 26. this is what the drawing becomes:

And to think I was that hideous only a month ago...

Making it up as she goes along?

I just noticed Judith Sloan making a comment in a Catallaxy thread that didn't sound right:

Could that line about Tasmania be true?

In 2013, the Premier was claiming 27,000 public servants, but the person who wrote this post said that if you add in employment in Tasmanian government owned bodies, it's more like 33,000.   Then someone in comments points to a 2010 report which said this:

New figures released by the Australian Bureau of Statistics yesterday show 40,900 Tasmanians were employed by the State Government in June, more than 17 per cent of the entire state workforce.
The wages bill for state public servants also leapt by nearly 19 per cent in the past year, gobbling up 53 per cent of the state’s limited Budget in salaries.
The State Government now provides more than one in six of all jobs in Tasmania, compared to an average of one in eight jobs being state government-reliant across the rest of Australia.
But when all public servants over three tiers of government federal, state and local government are taken into account more than one in five workers are employed by a government of some kind in Tasmania, compared to one in eight nationally.

And, by the way, this report from Tasmanian Treasury in February this year says there are about 241,000 employed workers in the State.

Seems to me that for Judith's claim to be correct, there would need to be at least 3 times more public servants there than there actually are.

Quite the gaff from an economist who is routinely rudely dismissive of all economics commentators she disagrees with. 

Update:  more facts and figures on Tasmanian workforce here.  Seems to me that, even if you were talking full time employees (about 145- 150,000), and also treating every public servant  as such, there is still no way her quip could be true.

I am failing to see how the mistake could even have been made...

Aging graphically

From a New York Times article that talks about European (and other countries') ideas about how to get people to have more babies comes this chart:

 

One suspects the situation in Japan just can't happen.   Immigration, at least, would have to increase, one would think.  There will be lots of empty houses for migrants to move into, anyway....

Maybe more time before there are no stars in the sky?

Accelerating universe? Not so fast

Let's hope there is no connection

Mass beaching fuels fears of impending quake | The Japan Times

The mass beaching of over 150 melon-headed whales on Japan’s
shores has fueled fears of a repeat of a seemingly unrelated event in
the country — the devastating 2011 earthquake and tsunami that killed
over 18,000 people.

Despite a lack of scientific evidence linking the two
events, a flurry of online commentators have pointed to the appearance
of around 50 melon-headed whales — a species that is a member of the
dolphin family — on Japan’s beaches six days before the monster quake,
which unleashed towering tsunami and triggered a nuclear disaster.

The junk science Senator

David Leyonhjelm writing in the AFR last week:

The only losers would be the major wind-energy generators, which are eagerly waiting to build dozens of new wind farms in an effort to meet the target and get on the subsidy gravy train. Against that, many people are hoping these are never built, among them those who suffer adverse health effects from the inaudible infrasound they generate...

Krugman on laughing Laffer

The Laffer Swerve - NYTimes.com

The article in the Washington Post he links to is worth reading too...

Drug madness

Experience: my anti-malaria drugs made me psychotic | Life and style | The Guardian

I had heard that there was one anti-malarial drug that often gave people vivid nightmares; I assume it was Lariam as described in this interesting first hand account of how it sent one young guy completely psychotic for a time.   I didn't realise that it could have that drastic an effect.  Lots of people in comments tell of their bad experiences with the drug, too. 

Fat but happy?

Underweight people face significantly higher risk of dementia, study suggests | Society | The Guardian

People who are underweight in middle-age – or even on the low side of
normal weight – run a significantly higher risk of dementia as they get
older, according to new research that contradicts current thinking.

The results of the large study, involving health records from 2
million people in the UK, have surprised the authors and other experts.
It has been wrongly claimed that obese people have a higher risk of
dementia, say the authors from the London School of Hygiene and Tropical
Medicine. In fact, the numbers appear to show that increased weight is
protective.

At highest risk, says the study, are middle-aged people with a BMI
[body mass index] lower than 20 – which includes many in the “normal
weight” category, since underweight is usually classified as lower than a
BMI of 18.5.

These people have a 34% higher chance of dementia as they age than
those with a BMI of 20 to just below 25, which this study classes as
healthy weight. The heavier people become, the more their risk declines.
Very obese people, with a BMI over 40, were 29% less likely to get
dementia 15 years later than those in the normal weight category.

This will set the fat cat amongst the public health policy pigeons.

Good news for me, at least, with my determined effort to keep at the very edge of BMI of 25.  (Actually, it seems according to one calculator, a 1 cm difference in my height is the difference between 25 and 26.  I must measure myself, somehow, again.)