PROSTO24: Unraveling Cosmological Mysteries

Ethan Siegel, an American theoretical astrophysicist and science journalist renowned for his “Starts With A Bang” column, consistently addresses pivotal questions in modern cosmology. Recent articles, translated by @avshkol, delve into contentious aspects of the nature of expanding space and the fundamental properties of light.

The Nature of Expanding Space: Stretching Existing or Creating New?

One of the central inquiries explored by Siegel concerns the mechanism of the Universe’s expansion. Is it a process where existing space stretches, or is new, additional space continuously being created? This question is intrinsically linked to deeper, as-yet-unresolved issues, such as:

  • Is space quantized, or is it an absolutely smooth and continuous structure?
  • Does expansion truly exist, or is it merely an illusion perceived by observers?
  • Will the expansion continue indefinitely, or will it eventually give way to contraction?
  • Where does the Universe derive the energy for this expansion: was it inherent from the Big Bang, or does it originate from an external source?

It is important to note that Siegel’s article primarily focuses on framing the core question about the nature of expansion, rather than providing definitive answers to these complex cosmological enigmas.

The Eternity of Light and the Debunking of the ‘Aging Light’ Hypothesis

In another significant publication, Ethan Siegel examined the nature of light, discussing whether light can “age” or “lose energy,” and if photons can disappear, especially in a scenario of infinite universal expansion. This topic is particularly relevant because the “aging light” hypothesis was historically proposed as an alternative explanation for Hubble’s red-shift, which is now the primary evidence for the Universe’s expansion.

As @avshkol points out, the aging light hypothesis, put forth by Fritz Zwicky in the 1930s to explain the observed red-shift of galaxies, was subsequently disproven. Interestingly, it was Zwicky who later proposed the concept of hidden mass, which we now know as dark matter. Modern scientific data confirms that photons do not “age” or lose energy during their journey, and the observed red-shift is a consequence of the expansion of space itself.