13
votes
Could Earth's Zircon (used in geological dating) have formed in extraterrestrial events before the Earth was formed?
It would seem strange to find that the oldest material found on Earth all formed in some extraterrestrial event that post-dates the ages of the oldest meteoritic material in the Solar System.
The ...
- 128k
8
votes
Could Earth's Zircon (used in geological dating) have formed in extraterrestrial events before the Earth was formed?
Zirconium is an element, thought to be the product of the S-process in asymptotic giant branch stars.
Zircon is a mineral, zirconium silicate, used in geological dating. Crystals of zircon form at ...
- 18.9k
4
votes
Accepted
Is Each Day the Same Duration?
Yes, the solar day length varies from 24 hours - ~22 seconds to 24 hours + ~30 seconds. Here's a graph for 2022, computed for apparent solar noon at Greenwich, using data from JPL Horizons
The ...
- 11k
2
votes
Is Each Day the Same Duration?
Yes, the length of the day varies.
This is graphically captured in the analemma, which I will display w/o explanation (other than the photo of the sun is taken at the same local time throughout the ...
- 31.6k
1
vote
Can a receding body due to the accelerated spacetime expansion be "rescued"?
In GR, you can find any kind of setup you like, you just need the right initial conditions for the mass density and its derivatives. However, cosmology studies the universe as a whole, in an averaged ...
- 215
Only top scored, non community-wiki answers of a minimum length are eligible