The Skeptical Teacher

Musings of a science teacher & skeptic in an age of woo.

Posts Tagged ‘gravitation’

Merry Newtonmass!

Posted by mattusmaximus on December 23, 2011

It’s almost December 25th, and while some people are celebrating certain holidays (Dies Natalis Solis Invicti!), one thing I like to do is take a little time to recognize one of the greatest contributors to modern science: Sir Isaac Newton.  Newton was born on December 25th, 1642 (according to the old-style Julian calendar)…

I totally stole this image from Skeptico 🙂

Isaac Newton was an English physicist and mathematician.  The son of a yeoman, he was raised by his grandmother.  He was educated at Cambridge University (1661-1665), where he discovered the work of Rene Descartes.  His experiments passing sunlight through a prism led to the discovery of the heterogeneous, corpuscular nature of white light and laid the foundation of physical optics.  He built the first reflecting telescope in 1668 and became a professor of mathematics at Cambridge in 1669.  He worked out the fundamentals of calculus, though his work went unpublished for more than 30 years.  His most famous publication, The Principia Mathematica (1687), describes his works on the laws of motion (now named for Newton), orbital dynamics, tidal theory, and the theory of universal gravitation, and is regarded as the seminal work of modern science.  He was elected president of the Royal Society of London in 1703 and became the first scientist ever to be knighted in 1705.  During his career he engaged in heated arguments with several of his colleagues, including Robert Hooke (with whom he argued over authorship of the inverse-square relation of gravity) and Gottfried Leibniz (over the authorship of calculus).

Of course, while Newton was certainly no saint (he had a reputation for being kind of a nasty guy, especially to his academic opponents, and he also dabbled in alchemy, Biblical numerology, divination, the occult and many other things we’d consider quite woo-ish today), we can see from his accomplishments listed above just why he is regarded as one of the greatest scientists of all time, and it is for those contributions to humanity that we remember him.

So this December 25th, take some time to raise a glass, and perhaps admire a falling apple, to toast Isaac Newton and his legacy.  Cheers! 🙂

Posted in humor | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 1 Comment »

More Media Fail and Silliness: Lunar Effect Babies

Posted by mattusmaximus on August 17, 2011

This week there’s been a story going around the media about a supposedly huge jump in births in a Sacramento hospital where “45 babies were delivered in 48 hours.”  Now that may or may not sound very unusual (it ends up it isn’t that strange – read on), but the really weird aspect of this is the claim made by the hospital officials with nary a skeptical thought:

“The human body is 80 percent water, after all. And, given that both menstruation and ovulation roughly follow a lunar cycle – occurring on a monthly basis – it doesn’t seem too far off to think that the moon could have a say in childbirth as well,” hospital officials said.

And, of course, the supposed mechanism for this “lunar effect”, as espoused by the hospital spokesman, is gravitational in nature:
According to the news release, the moon’s gravitational pull “can control a woman’s body” the same way the moon’s gravity controls tides.
*Cue spooky music…
Image courtesy of

First of all, the fact that 45 babies were born in 48 hours is not that significant.  Note the article states that there have been a total of 325,000 babies delivered at the hospital since 1937.  If you do the math, then this comes out to an average of about 12 babies per day – compared to the claim in the article (which basically averages out to about 22 or 23 babies in one day), this seems not very extraordinary because it shows that there was a weekend where the hospital had only double the average number of births!  100 times the average number of births would be statistically significant, but not 2 times the average.

Then there’s the stupid claim about the “lunar effect”.  Not only is this a bogus claim – click here to see why not – but it is also implausible from the standpoint of basic physics.  The hospital spokesman makes a common claim about the “lunar effect” being gravitational in nature, like the tidal effects on the Earth’s oceans.  However, if one takes a moment to work through the mathematics, this arguments falls apart pretty quickly.  For example, I perform the calculations for the tidal effects of the moon (whether it is full or not is irrelevant) on a person in my physics classes, and it ends up the tidal forces that act upon a person are stupendously small – about one-billionth the weight of a paperclip!  So whether or not you decide to wear a hat or use hair gel on any given day has more gravitational influence on you than does the tides from the moon!

That’s because the strength of the tidal forces that act on an object are proportional to the size of that object.  In the case of a large planet, like the Earth, the relative difference between gravity from one side of the planet to the other (this difference is the tide itself) is pretty big since the Earth is big.  But humans are so small on this size scale that the difference in gravity (tide) on us is miniscule.

So the next time you gaze upwards and see the full moon, appreciate it for all its beauty and wonder.  But don’t worry about it making you crazy; the failure of the media to accurately report science is a bigger threat of making you nuts 😉

Posted in astrology, mathematics, media woo, physics denial/woo | Tagged: , , , , , , , , , , , , , , , , , , , | 1 Comment »

Asteroid Apophis to Hit Earth in 2036? Calm Down, the Sky is NOT Falling

Posted by mattusmaximus on February 9, 2011

In recent days, one of the more popular news stories flying around the Internet has to do with a supposed “doomsday” asteroid called Apophis. And, according to some idiotic journalists who seem to want to push a sensationalistic “news” story, this asteroid is going to hit the Earth in 2036 with devastating consequences – in short, they say this is going to happen…

Well, I’m here to tell you that this is, to use the scientifically-accurate phrase, a complete load of crap. That’s because the original story, which came via a Russian “news” outlet, has been completely and thoroughly refuted by NASA and scientists worldwide…

Will Apophis Hit Earth in 2036? NASA Rejects Russian Report

In 2004, NASA scientists announced that there was a chance that Apophis, an asteroid larger than two football fields, could smash into Earth in 2029. A few additional observations and some number-crunching later, astronomers noted that the chance of the planet-killer hitting Earth in 2029 was nearly zilch.

Now, reports out of Russia say that scientists there estimate Apophis will collide with Earth on April 13, 2036. These reports conflict on the probability of such a doomsday event, but the question remains: How scared should we be?

In answer to that question, I think we shouldn’t really be scared at all.  When you crunch the latest numbers, the probability that Apophis will actually impact the Earth in 2036 is about 1-in-250,000.  If you work that out to a percentage, it comes out to a 0.0004% chance the asteroid will hit Earth.  That’s a pretty slim chance, and certainly nothing to get all upset about, in my opinion.

Let’s think of it this way: compare the probability that Apophis will hit Earth in 2036 with the chances of other unfortunate events (as reported by Popular Science magazine)…

Lifetime odds of dying from:

Any accident: 1 in 36

A motor vehicle accident: 1 in 81

A firearm: 1 in 202

Poisoning: 1 in 344

A falling object (terrestrial): 1 in 4,873

Drowning in a bathtub: 1 in 10,455

Being caught in or between objects: 1 in 29,860

Suffocation by a plastic bag: 1 in 130,498

So that means that you are about twice as likely to die by being suffocated in a plastic bag as compared to the chances that this “killer” asteroid Apophis will wipe out planet Earth.  Stop and think about that for a moment… now, are you suddenly going to start demanding the recall of all plastic bags from society in order to protect humanity?  No?  Good.

Now, please don’t get me wrong – I think the issue of tracking & cataloging near-Earth objects (NEOs) is a very important one, precisely because we have solid evidence that NEOs such as asteroids & comet fragments can and do hit the Earth.  In fact, this happens all the time, but the regular impacts are from smaller objects; the big, “planet-killer” type objects are fewer in number so the chances of one coming our way is comparatively small.  But it could happen, and with the implications being what they are (i.e., the destruction of human civilization on Earth being among the worst-case scenarios) it would be prudent for us to invest at least some resources into these questions.  And we have invested such resources into NASA’s NEO Program.

So, in conclusion, is the sky falling with regards to Apophis?  No.

Should you go buying your own “asteroid apocalypse” bunker?  No.

Should we then turn a blind eye to the potential threat of NEOs?  No.

Should we invest a reasonable amount of money into researching this issue?  Yes.

Interestingly enough, one thing we really can do when Apophis makes its closest approach to Earth in 2036 is use the opportunity to learn more about asteroids and the early solar system.  In fact, some scientists already have plans to use Apophis as an amazing research opportunity!

If you’d like to know more about Apophis, and the related physics & astronomy behind it, I suggest taking a look at this entry over at Phil Plait’s Bad Astronomy blog.

Posted in doomsday, media woo, space | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 9 Comments »