A page to list various examples of serendipity in knowledge discovery.

Excerpts from How to See the Invisible Universe: Telescopes that detect long-wavelength signals offer clues about the Big Bang, the centers of black holes, and the origins of life:

  • The German physicist Wilhelm Roentgen discovered X-rays after he saw an unexpected glow from a fluorescent screen in his lab.
  • The French physicist Henri Becquerel discovered radioactivity when he noticed that photographic film stored in a drawer had become unaccountably fogged.
  • Likewise, observations of the invisible universe, detectable in long wavelength photons in space were first found by accident, in 1964. In a project to develop orbiting communications satellites, researchers Arno Penzias and Robert Wilson, at Bell Telephone’s New Jersey laboratories, used a ground-based antenna pointed at the sky. Unexpectedly, it picked up a signal of unknown origin at a wavelength of 7.35 cm, which remained constant no matter where in the skies the antenna pointed. To study this radiation without interference from the Earth’s atmosphere, in 1989, NASA launched the Cosmic Background Explorer (COBE) satellite into space, equipped with instruments to measure the strength and wavelength of millimeter and centimeter waves.
  • The results, published in 1993, showed a distinctive peak at 1.07 mm, a “blackbody curve,” which describes the electromagnetic waves emitted by any object above absolute zero temperature. 
  • To closely examine the density variations, in 2009, the European Space Agency (ESA) launched its Planck spacecraft, named after Max Planck, who derived blackbody theory in 1900.
  • The final results, announced in 2018, give the most precise and complete description of the universe to date. We now know that it is approximately 13.8 billion years old, and is made of 4.9% normal matter, 26.6% dark matter, and 68.5% dark energy.
  • To underline the point: 95.1% of the cosmos consists of entities unlike anything on Earth, whose nature we do not fully understand—we can only speculate until we learn more.
  • In 2009, the Event Horizon Telescope (EHT) research consortium set out to image a black hole at the center of a distant galaxy denoted as M87.
  • After recording and analyzing data measured at a wavelength of 1.3 mm, in April 2019, EHT presented its image. The by-now-familiar picture clearly shows a dark “shadow” inside the glowing accretion disk at the center of M87. The shadow closely surrounds the black hole’s event horizon, making this the nearest we have come to pinpointing a black hole itself. The data shows that the mass within the black hole is 6.5×109 times that of our Sun.
  • This supports what has been long surmised, that “supermassive” black holes lie at the center of galaxies, where they produce accretion disks called quasars, the brightest known astronomical objects.