May 26, 2020

Review: What Are Gamma-ray Bursts? by Joshua S. Bloom.

Out from Princeton Press!

In 1888, astronomer Simon Newcomb made the now infamous quip that “we are probably nearing the limit of all we can know about astronomy…” One has to wonder what these 19th century scientists would make of the wonderful cosmological menagerie of black holes, energetic galactic nuclei, and the topic of today’s review. What Are Gamma-Ray Bursts? By Joshua S. Bloom serves as a modern snapshot of one of modern astronomy’s most enigmatic beasties. Out from Princeton University Press, this is a work that doesn’t shy away from the “Mathiness” as it explores these bursts on the edge of space.  In 1967, the United States Vela series of spacecraft were on watch as orbiting gamma-ray sensing platforms aimed at monitoring Soviet nuclear activities during the Cold War. These spacecraft discovered highly energetic particles emanating from distant space, and it has taken astronomers decades to come up with observational models that could explain the existence of objects with such explosive force. Professor Bloom draws off of data from the Compton, BATSE, and NASA’s hugely successful Swift satellite in orbit that have given us hard data on these objects. Such bursts have been further categorized into short and long duration bursts, with the dividing line being a duration of about two seconds. As you can see, it has been nothing short of a technical challenge to build a network of instruments with a ‘Swift’ (hence the name!) reaction time capable of swinging into action to try and catch a counterpart fading across the spectrum.

The world of gamma-ray bursts is a brave new one populated by hyper-novae, magnetars, and binary pulsar and/or black hole mergers. Cosmology is really coming on to its own, as new instruments like LIGO and Ice Cube may soon give us complimentary views on the sky in both gravity waves and neutrino emissions and enable us to further probe the universe and these and other exotic objects such as GRB’s. These explosions have no shortage of “Wow!” factor about them; for example, GRB 080916C was one of the most powerful explosions yet on record, releasing the equivalent of the output of 7,000 supernovae in only 23 minutes! Good thing it was “only” 12.2 billion light years away…

Mr. Bloom also does well in laying a thorough theoretical framework as to where our technical knowledge stands. Cosmology is like a well-built brick house, with one observational foundation underpinning another. Often, would-be alternate hypothesis proposers and detractors of modern cosmology (I’ve met more than a few, believe me!) fail to realize that the bridges have already been built along lines of converging evidence, and modern cosmologists have long since moved on to where the really intriguing questions are at.

In short, be sure to check out What Are Gamma-Ray Bursts? To get a look at one of the most exciting fields of modern astronomy. It all makes one wonder; how bizarre will our knowledge of the universe be one century from now?

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