Astro Bloopers

May 28, 2007

Ah, ’tis May time and exams are here ! I hear the distant scratching of a thousand pens in echoing sports halls and I know that all is right with the academic world. The future hangs in the balance; careers are won and lost; the glittering prizes brighten and fade, as inspiration approaches and recedes. But, thanks to Statistics, there are certainties in this contingent world. We just know that most students will do kinda ok; a handful will stun us; and a handful will turn in utter gibberish. Here are some of my favourites, collected from a few years worth of astronomy exams.

Most are from first year Astronomy courses for a wide range of students – what I believe our American chums call “Astronomy for Poets” or “Scopes for Dopes”. But some are from junior and senior honours students .. see if you can tell which..

All real folks.

  • Doppler shift is an effect which doesn’t take place on the poles of the earth, but it does everywhere else.
  • Black bodies do not emit any light, as they are a box with a tiny hole in. Light enters the hole, bounces around the box, and cannot get out again.
  • IR observations tend to be used for trying to find new plants, which at 300K fit neatly in the IR spectrum.
  • Physics is terrestrial whereas astronomy is conducted on an astral plane.
  • IR astronomy is carried out with an instrument called a bola meter, which is made of geranium.
  • Interferometry works because when the dishes are a certain distance apart the radio waves are syncopated.
  • We know there is dark matter in galaxies as they rotate faster than they ought to, so dark matter must be absorbing some of the light…
  • X-ray astronomy must be carried out from space otherwise the radiation would have a damaging effect on Earth, causing cancer and so on.
  • For spiral galaxies, the linewidth technique is known as Tully-Fisher, whereas for elliptical galaxies it is the Fabry Perot method.
  • part of answer to “describe the universe as seen at different wavelengths”….. The infrared universe is a great deal more colourful, although the colour is often false and generated by a computer.
  • Black-body radiation requires dark matter.
  • The spectral shape of the radiation from black-bodies is determined by the allocation of nearby bodies, as the gravitational attraction from these can “stretch” the radiation and make it more elliptical.
  • The rotation curves of galaxies are the wrong shape. This is because dark matter is concentrated towards the centre, absorbing the light and preventing us from obtaining accurate velocities for this part of the galaxy.
  • Astronomy can be seen as applied physics, and indeed most great astronomers have also been great physicians.
  • In astronomy, all experiments conducted are out of our control.
  • We now know of two black holes, Cygnus I and the one at the centre of the Kerr galaxy.
  • A dynamically relaxed system obeys the viral theorem.
  • If it weren’t for Physics, Astronomy would only be the observation of the pretty bright specs we can see in the sky.
  • Answer to “how would Earth’s orbital velocity change if sixteen times closer to the Sun ?”… If the Earth were sixteen times closer to the Sun, it would vaporise and so its orbital velocity would be zero.
  • X-rays from around black holes are produced by accension belts.
  • The radio emission from quasars is not blackbody emission because that is a theoretical concept and does not actually exist in the universe.
  • White dwarfs are white because they are mostly made of carbon and oxygen i.e. CO, which is a white solid.
  • There is no spheroidal component in the Milky Way, as at night we can see that all the stars are in a thin line.
  • When forced closer together, the electrons buss about more violently.
  • A Type II supernova is the death of a star resulting in a big explosion. This only happens once per star.
  • A pulsar is a neutron star that emits ultra-violent radiation.
  • The Sun is a main sequence star. This is the most common type of star in the solar system.
  • The denser the body the less radiation they emit. The most extreme case being “black body” radiation where no detectable radiation is emitted.
  • The mass of the solar system is 10**12 solar masses. When divided by all the stars we estimate, that comes out at 30 solar masses per star.
  • We calculate the distance to the Sun by bouncing radar signals off Venice at six monthly intervals.