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New Findings Deepen the Mystery of Fast Radio Bursts
An anonymous reader writes: Last week, it was reported that the mystery of fast radio bursts were solved, and that they were due to the merger of a neutron star with another collapsed object, well outside of our galaxy. However, not only was that analysis fundamentally flawed, but a new paper out today identifies fast radio bursts that repeat, a dealbreaker for the merger scenario. Instead, it's thought that these events come from the evolution of young neutron stars, as the data show an extragalactic but non-transient origin for these bursts. Planned follow-up observations plan on identifying the source locations as well as their true nature, and discerning whether all fast radio bursts have the same origin, or whether there are multiple different classes.
>> fast radio bursts that repeat, a dealbreaker for the merger scenario
Do we know this isn't gravitational lensing? (https://en.wikipedia.org/wiki/Gravitational_lens)
He seems to have a better grasp than you do:
As far back as the 3rd century BC, Eratosthenes had correctly computed the circumference of the Earth by using simple geometry and studying the shadows cast by objects at two different locations: Alexandria and Syene (modern-day Aswan).[30] Eratosthenes's results were confirmed by a comparison of stellar observations at Alexandria and Rhodes, carried out by Posidonius in the 1st century BC. These measurements were widely known among scholars, but confusion about the old-fashioned units of distance in which they were expressed had led, in Columbus's day, to some debate about the exact size of the Earth.
Toscanelli's notions of the geography of the Atlantic Ocean, which directly influenced Columbus's plans
From d'Ailly's Imago Mundi Columbus learned of Alfraganus's estimate that a degree of latitude (or a degree of longitude along the equator) spanned 56 miles, but did not realize that this was expressed in the Arabic mile rather than the shorter Roman mile with which he was familiar (1,480 m).[31] He therefore estimated the circumference of the Earth to be about 30,200 km, whereas the correct value is 40,000 km (25,000 mi).
https://en.wikipedia.org/wiki/Christopher_Columbus#Geographical_considerations