Tag Archives: cosmology

Hubble observed a supernova brighter than its galaxy

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A supernova releases as much energy in days as our Sun does in several billion years. In 2018, the Hubble Space Telescope observed a supernova 70 million light years away, which outshone its entire galaxy until it faded away over the following year.

This video zooms into the barred spiral galaxy NGC 2525, located 70 million light-years away in the southern constellation Puppis. As we approach an outer spiral arm a Hubble time-lapse video is inserted that shows the fading light of supernova 2018gv. Hubble didn’t record the initial blast in January 2018, but for nearly one year took consecutive photos, from 2018 to 2019, that have been assembled into a time-lapse sequence. At its peak, the exploding star was as bright as 5 billion Suns.

While nuclear fusion and a slow neutron capture process form all the elements up to 83 (Bismuth), the elements are also produced very rapidly in supernovae along with all the heavier elements. Supernovae have produced the the bulk of the universe’s precious metals, silver, platinum and gold, and are responsible for the creation of the heaviest elements up to uranium.

Supernovae like this all peak at the same brightness and so can be used to accurately measure the distance of their host galaxy, allowing accurate measurement of the universe’s expansion rate. The current best estimate is that the universe is expanding at a rate of 69.3 km/sec/Megaparsec plus or minus 0.8. That means that for every Megaparsec (about 3 million light years) that you go out, the Universe is expanding 69.3 km/sec faster. So that means that NGC 2525 is moving away from us at a speed of around 1500 km/s or half a light year each century.

Other worlds – the birth of a new solar system

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Update: November 2014. Astronomers have captured the best image ever of planet formation around an infant star, using the Atacama Large Millimeter/submillimeter Array’s (ALMA) new high-resolution capabilities. The image reveals in astonishing detail the planet-forming disk surrounding HL Tau, a Sun-like star located approximately 450 light-years from Earth in the constellation Taurus.

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Other worlds

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As a teenager I was fascinated by astronomy and cosmology and read voraciously as well as spending many hours outside at night with my telescope and Norton’s Star Atlas. During my brief years as a physicist in the 1970s, I kept up with the literature and was aware that some astronomers were attempting to detect planets around other stars by detecting the gravitational jiggling of the star around which the planet was orbiting. But these movements were slightly beyond detection by the technology of the day.

Headlines with messages like “First Planet Found Outside Our Solar System” appeared in newspapers dozens of times, at least twice in the New York Times, and once on the front page. But all these announcements were subsequently found to be wrong. And in one notorious incident, it was later found that the astronomer had detected not movements in stars, but movements in the telescope itself. So I was stunned to discover on reading the book “The Stardust Revolution” that new detection methods combined with space-based telescopes had resulted in the proven discovery of nearly 2000 exoplanets.

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Origins — the fascination of ancestors — recent, ancient, extreme

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I have had an interest in the history of my family since childhood, when I wrote a short history of the Mathers family that drew heavily on documents and recollections of family members, particularly those of a great-uncle and great-aunt born in Scotland in the 19th century. When I discovered Tolkien’s Lord of the Rings trilogy as a teenager, I was fascinated by the genealogical charts in the Appendices to the Lord of the Rings. For some reason, I find the tracing of connections to a larger history deeply satisfying. Over the last ten years, I returned to researching my ancestry using the powerful tools offered by the Internet, with access to databases and historical records that I would not have dreamed possible before.

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