I don’t know how much controversy there is over the time. I assume the estimate is calculated based on current knowledge of heliophysics. My particular source is the 2017 book “Totality” by Mark Littmann and Fred Espenak. The latter is an astrophysicist emeritus at NASA’s Goddard Space Flight Center.
Interesting fact: A photon produced at the sun’s core cannot travel directly to the surface, due to being absorbed and re-emitted by other particles countless times. It takes an average of 10,000,000 years for that photon to escape the sun – then another 8.3 minutes to travel to Earth.
Not any more. Now they have a supplemental list of names. From the National Hurricane Center:
“In the event that more than twenty-one named tropical cyclones occur in the Atlantic basin in a season, any additional storms will take names from an alternate list of names approved by the WMO. "
I don’t know how much controversy there is over the time. I assume the estimate is calculated based on current knowledge of heliophysics. My particular source is the 2017 book “Totality” by Mark Littmann and Fred Espenak. The latter is an astrophysicist emeritus at NASA’s Goddard Space Flight Center.