The Grand Tour with Dr. David Helfand

David Helfand. Photo: Karl Withakay [CC BY-SA 4.0 (]
The event may have been listed as The Grand Tour, but a more accurate title would be The Grand Tour de Force.  On May 31, Dr. David Helfand performed an incredible feat:  to compress most of the basic concepts in astronomy into a single, coherent and highly entertaining lecture of 56 minutes.  Which included accompanying excerpts of Beethoven’s ninth symphony and an occasional Viennese waltz.  Visibly enjoying the exercise, Helfand wowed his Columbia University audience with his humor and erudition.  In short, a master at work.

A Columbia professor of astronomy and physics, Dr. Helfand is past president of the American Astronomical Society and former chair of the University’s astronomy department.  He has also been a visiting scientist at the Danish Space Research Institute and a Sackler Distinguished Visiting Astronomer at Cambridge University.  Helfand’s latest book, A Survival Guide to the Misinformation Age, is available from Amazon and other booksellers.

A list of the topics he touched on in his lecture reads like the syllabus for a year-long introduction to an astronomy course:

  • The Electromagnetic Spectrum
  • The Moon Landing
  • Mars Rovers
  • Cosmic Distances and Time
  • The Solar System
  • Nebulae and Stellar Nurseries
  • Radio Astronomy
  • Star Clusters
  • Stellar Astronomy & Nuclear Fusion
  • Stellar Death and Planetary Nebulae
  • Supernovae and their Remains
  • Galaxies and Galaxy Mergers
  • The Hubble Deep Field
  • The Redshift
  • Gravitational Lensing
  • Large-scale Structure
  • The Cosmic Microwave Background
  • Dark Matter and Dark Energy

To start, Helfand used music to explain the thin slice of the electromagnetic spectrum that human eyes have evolved to perceive.  Imagine that you were capable of hearing only one octave of sound; you would miss out on the richness of an orchestra, with instruments ranging in pitch from the very low to the very high.  Our perception of light is analogous.  And as he puts it, the history of the past 50 years in astronomy has been one of expanding our vision beyond just visible light, revealing unseen constituents of the universe, thereby revising our models to explain it.

The cosmic microwave background. Courtesy: NASA / WMAP Science Team.

From there, he moved on seamlessly to the other topics above, all interspersed with images from the Hubble, Chandra and Spitzer space telescopes and occasionally, more music.

Helfand closed his talk by calling our attention to the number, 100 billion.  A human brain has about 100 billion neurons, each composed of about 100 billion atoms.  And in space, an average galaxy has 100 billion stars, and the observable universe has on the order of 100 billion galaxies we can observe.  Now the fact that these numbers are all the same is, as he put it, is a complete coincidence!  But the fact that 100 billion neurons can comprehend all this is what makes cosmology exciting.

A grand tour de force indeed.