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Massive Stars and their approximate Size

Astronomers have found massive stars in the early universe, primarily located in distant galaxies that formed shortly after the Big Bang. These regions are often studied through advanced telescopes capable of observing very distant light, such as the Hubble Space Telescope and the upcoming James Webb Space Telescope. In terms of size, these monster stars can have diameters ranging from about 100 to over 300 times that of our Sun. The Sun’s diameter is approximately 1.4 million kilometers (about 864,000 miles), so these massive stars could be approximately 140 million to over 420 million kilometers (about 87 million to 261 million miles) in diameter.

Why the day is 24 hours long: Astrophysicists reveal why Earth's day was a constant 19.5 hours for over a billion years

Astrophysicists have revealed how the slow and steady lengthening of Earth's day caused by the tidal pull of the moon was halted for over a billion years. They show that from approximately two billion years ago until 600 million years ago, an atmospheric tide driven by the sun countered the effect of the moon, keeping Earth's rotational rate steady and the length of day at a constant 19.5 hours. Without this billion-year pause in the slowing of our planet's rotation, our current 24-hour day would stretch to over 60 hours. The paper offers a new perspective on how global warming will affect the length of our day and validates global circulation models as a climate modelling tool.

from Space & Time News -- ScienceDaily https://ift.tt/El7VTeR

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