In 1917, a year after Albert Einstein’s general theory of relativity was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the entire universe. For anyone else, this might seem an exceedingly ambitious task—but this was Einstein.
Einstein began by applying his field equations of gravitation to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—his equations told him that the universe could not stay static: it had to either expand or contract. Einstein chose to ignore what his mathematics was telling him.
The story of Einstein’s solution to this problem—the maligned “cosmological constant” (also called lambda)—is well known in the history of science. But this story, it turns out, has a different ending than everyone thought: Einstein late in life returned to considering his disgraced lambda. And his conversion foretold lambda’s use in an unexpected new setting, with immense relevance to a key conundrum in modern physics and cosmology: dark energy.
By Govert Schilling
Just over a week ago, at three miles above sea level in the Chilean Atacama desert, Atacameño indians offered gifts to Mother Earth in a traditional ceremony to bless a decidedly modern object: the Atacama Large Millimeter/submillimeter Array (ALMA). Four days later, on March 13, the largest-ever ground-based astronomical observatory was officially inaugurated. “ALMA is now a reality, and not a fairy tale anymore,” said Dutch astronomer Thijs de Graauw, the project’s director.
ALMA (Spanish for “soul”) consists of 66 antennas, most of them 40 feet across. They are equipped with sensitive receivers to detect millimeter and submillimeter waves from space – radiation in between radio waves and infrared light. This relatively long-wavelength radiation is emitted by the coolest objects in the Universe, such as the dark molecular clouds that spawn new stars and planets. What’s more, interstellar molecules, including complex hydrocarbons and other molecules necessary for life, can only be identified using this type of radiation. Cosmic millimeter and submillimeter radiation has never been observed in much detail before, so astronomers all over the world have eagerly anticipated the ALMA inauguration.
Amir D. Aczel writes often about physics and cosmology. His book about the discovery of the Higgs boson, Present at the Creation: Discovering the Higgs Boson, is published in paperback by Broadway Books in November 2012.
If somebody told you that there are angels floating in space, observing our world and forming their impressions of our everyday reality, you would think that this person is nuts—a religious fanatic with an active imagination, and certainly not a scientist. Scientists, as we all know, are rational beings who believe only in what nature reveals to us through experimentation and observation, coupled with theory that is never divorced from the physical measurements they make. The link between the two remains tightly regulated through the strict rules of the scientific method.
So how do you explain the bizarre fact that, for about five years now, some of the world’s most prominent physicists have been describing a scenario—which they seem to truly believe may be real—in which, instead of the Biblical angels, space is permeated by disembodied brains?
These compact, conscious observers, called “Boltzmann brains,” cruise the vastness of intergalactic space, and beyond it, to the infinite “multiverse” that some scientists believe exists outside the reaches of the universe we observe through our telescopes and satellites. Their consciousness makes the Boltzmann brains recreate our reality. They imagine life such as the one you and I believe we are experiencing here on Earth, to the point that these brains in space may think that they are living on a planet like ours, that they may even be us. Some recent physics papers and commentaries have even explored the possible limits on the number of Boltzmann brains in the universe as compared with “real” brains, in an effort to estimate the probability that we are real rather than Boltzmann entities.