Tag Archives: physics

Consulting about physics over Skype

My callers fall into two very different categories. Some of them cherish the opportunity to talk to a physicist because one-to-one conversation is simply more efficient than Google. They can shoot up to 20 questions a minute, everything from: ‘How do we know quarks exist?’ to ‘Can atoms contain tiny universes?’ They’re normally young or middle-aged men who want to understand all the nerdy stuff but have no time to lose. That’s the minority.

The majority of my callers are the ones who seek advice for an idea they’ve tried to formalise, unsuccessfully, often for a long time. Many of them are retired or near retirement, typically with a background in engineering or a related industry. All of them are men. Many base their theories on images, downloaded or drawn by hand, embedded in long pamphlets. A few use basic equations. Some add videos or applets. Some work with 3D models of Styrofoam, cardboard or wires. The variety of their ideas is bewildering, but these callers have two things in common: they spend an extraordinary amount of time on their theories, and they are frustrated that nobody is interested.

Source: What I learned as a hired consultant to autodidact physicists | Aeon Ideas

What happens when an out of work theoretical physicist starts a business where anyone can call him on skype and ask questions for $50 / 20 minutes? Some really fascinating stuff. Mostly about how people absorb, or mis absorb, popular science.

We often forget that abstractions and models, are just that. Like maps, you file off all the interesting details to get a big picture. But a map of the US tells you very little about the stream in your back yard. The wildlife along it. When it floods. What vegetation grows because of that. The story is always deeper, more complicated, and more interesting the closer you look.

Cable news needs to go back to science class

I missed the whole balloon boy thing, it was a busy day, and happily none of the people I follow on twitter seemed to get wrapped up in it.  So it wasn't until later that night, once local news rolled on after network tv, that I saw the balloon soaring through the air.  After 2 seconds of footage I was really baffled that anyone thought there was a kid in there.

Balloon's rise because they are lighter than air.  Effectively that creates a force that pulls the thing up (that's a big simplification, but good enough).  If there had been a child amount of weight in the balloon the thing would have a pretty substantial force pulling down.  The balloon would be vertically stretched.  It was not.  This is pretty basic stuff, and not very hard to figure out.  The folks at Wired just posted something that goes through this in even more detail.

The whole story cycle represented the 2 things that I hate most about cable news at this point.  Giving far too much coverage to totally inane events (creating a self fulfilling prophecy and creating more of them), and spending so little time fact checking anything that goes on the air.  I guess I shouldn't be surprised given that the science team was deemed expendable, but I'm still disappointed.

Black Holes don't suck

Last night I learned quite a bit about super massive black holes at the Mid Hudson Astronomy Association month meeting in a great presentation by Dr Barry McKernan.  His overwhelming theme of the evening was that "Black Holes Don't Suck", as he wanted to break that myth.  Everything you've seen in science fiction on black holes is pretty much wrong.

A black hole is just a dark star, so small (relative to mass) that the escape velocity from it's surface is faster than the speed of light.  If you converted the earth into a black hole, it would be the size of a grape.  It would still have the mass of the earth.  The moon would still orbit it just the same.  But you'd be unable to see the thing you were orbiting.  The moon wouldn't fall into the earth, as the celestial mechanics don't change.

A very recent (last decade) discovery is that the hearts of most galaxies contain super massive black holes.  The one at the center of the milky way is 2 Million times the mass of the Sun, though only 10s of times as physically large.  That actually makes it smaller in radius than a lot of the brightest stars you can see at night, like Sirius and Betelgeuse.  Barry started the evening with a movie made of 10 years of observations of the center of the galaxy in which you could see stars moving around in arcs.  Zooming in on the data showed one star in particular whipping around something invisible, like it was a planet going around the sun.  This is part of the data that proved the existence of the super massive black hole in our galaxy.

A subset, less than 1%, of these galactic black holes are consuming dust.  Because dust clouds interact with themselves they effectively slow down over time (converting energy into light and heat).  This creates what are called Active Galactic Nuclei.  They are huge beacons of light at the center of galaxies.  Previously we call these things Quasars, Masars, Magnetars.  In the telescopes of 2 decades ago they look sort of like stars (they are point sources of light), but their light curves are all wrong to a be a star.  Now we can actually see both the "star" and the galaxy they are the center of.  If we get to see the disc top down, they outshine the rest of the galaxy by as much as 1000 times.

I asked the question, "if they outshine the rest of the galaxy, what would they look like if you were in their galaxy".  I saw the speakers eyes light up when I asked the question, so I knew I'd hit on a good one.  The answer, there is so much dust in the discs of galaxies that all that optical, uv, and x-ray light would get absorbed, then re-emitted as infrared.  You'd see a big infrared glow in the direction of galactic center.  You'd also probably see radio jets shooting out like spikes perpendicular to the plane of the galaxy.

All in all this was one of my favorite talks at the group to date.  Very informative, and presenting some great science.  If you have any interest in the stars, and are in the Mid Hudson Valley, you should come check out the group.  Friendly folks, spreading science, what could be better.