Prof Krys Doran

Hello everyone, I’m Professor Krys, a real-life Earth Science and Astronomy teacher! I am specialized in planetary geology and the formation of our Moon. If you have any questions about our planet or solar system please feel free to send me an Ask or @ me!


#Introduction #Astronomy #Geology #EarthScience #PlanetaryGeology #HigherEd
Sep 29 at 6:18pmWeb
Show threadczwolf ΘΔSep 29
Ah thats so rad, welcome!
Show threadMysturjiSep 29
@krysdoran
Question:
They say that Earth is ~4.5 billion years old. How old is the sun(older)? Did the impact that formed the moon reset Earths birthday?
Show threadMysturjiSep 29
@krysdoran
Also, when a star forms, is there a sudden “ignition event” when it changes from a proto-star to a main-sequence star, or is it a gradual process taking millions of years?
Show threadProf Krys DoranSep 29
The interior of an object needs to get to 100 million Kelvin to cause hydrogen fusion. From what I know, it’s a fairly sudden event. However, it takes millions of years for the gamma rays created during the proton-proton chain reaction to get out of a star, slowly losing energy and turning into visible light waves as they go, so you wouldn’t know for a long time if fusion had started!
Show threadProf Krys DoranSep 29
Great question! Our solar system is 4.6 Ga (billion) years old, which isn’t much older than the Earth! We think accretion was a pretty quick process. As for the Moon forming impact, it does not reset the clock! We set Earth’s age as starting at 4.54 Ga, and we call it the Hadean Eon. At around 4.50 Ga, the Moon-forming impact happened. Earth had to re-form part of the crust and mantle as the Moon formed from the debris. Then, at 4.00 Ga, Earth is cooled enough and the Archean Eon began!
Show threadAethonSep 29

@krysdoran

I have a question please?

I carry a pebble in my pocket to remind me of the brevity of my existence. It looks like a sea washed pebble made of very dark almost black rock, from a beach in the south UK. I think it is older than the dinosaurs but I can’t find anywhere that explains the lifecycle of a pebble to me that isn’t ai dross.

My thought it that is was a rock that was formed then eroded then buried then exposed and washed until it reached me.

Am I correct?

Show threadProf Krys DoranSep 29
You’re probably close to right! Most beach pebbles and sand have been transported long distances from the tops of mountains down to the sea by erosional transport mechanisms, often rivers! The transportation process slowly rounds the edges of the pebble until it reaches the ocean, then wave action takes over, rolling and smoothing the pebble even more. Some day, with enough time, the pebble could become a grain of sand!
Show threadCiaraSep 30
@krysdoran Welcome to the neighbourhood!
Show threadJake RaysonOct 1
@krysdoran
And a super cool avatar to boot!