Jon Lomberg was also the Design Director for the Golden Records mounted on the Voyager spacecraft, which seems a reasonable and epic way as any to close this little tangential thread

In summary, whether we like it or not, we are ALL hurtling around the galaxy at 240 kilometres per second 🥴

9/9

Disturbed Oort Cloud = visiting comets!

In Carl Sagan and Ann Druyan's COMET (1985), a 30 Myr cycle of the solar system "oscillating" above and beneath the galactic plane, rather than through spiral arms, is proposed as an extinction driver

(the "late Cretaceous comet shower", by Jon Lomberg)

8/

Key to all of this is the Oort Cloud - a (still hypothetical) giant disc and spherical shell surrounding the solar system, consisting of possibly trillions of frozen fragments from its formation.

Does this become more "disturbed" through spiral arms?

www.skyatnightmagazine.com/space-scienc...

7/

The various published articles and papers that connect the natural history of the Earth with the solar system's journey through the spiral arms of the galaxy are absolutely fascinating. Here's another:

6/

www.sciencedirect.com/science/arti...

Here's an interesting graphic that plots the solar system's travel. Note that major extinctions occur when the solar system is within a spiral arm:

Late Ordovician/Devonian: Norma Arm
Permian-Triassic & Triassic-Jurassic: Scrutum-Centaurus Arm
End Cretaceous: Sagittarius Arm

5/

"Did transit through the galactic spiral arms seed crust production on the early Earth?"

a fascinating article that suggests passing through the more dense spiral arms every 200 Myr triggers increased periods of cometary impacts

4/

pubs.geoscienceworld.org/gsa/geology/...

The spiral arms of our galaxy are not physical structures of fixed stars, but are density waves that rotate around the galaxy at a slower speed (210 km/s) than the stars (240 km/s)

(www.youtube.com/watch?v=Ixhz...)

So, our sun "outpaces" each spiral arm - which leads to an interesting theory..

3/

A NASA/JPL-Caltech depiction of the Milky Way, our barred spiral galaxy of 100-400 billion stars..

Our solar system is in a minor spiral arm, the Orion Arm.

It's easy to now picture the galaxy slowly rotating like a fixed pinwheel, with our sun a life-long member of it's spiral arm, right?

2/

Just to clarify - this cover illustration seems to be showing pterodactyls that have ROUNDELS on their wings??! Wild!

(That reminds us, we do have a somewhat out-there “Zeppelin vs Pterodactyls” thread ready for a rainy day..)

Also:

FESTIVAL OF PARK TALKS

We'll be doing two talks, alongside the Crystal Palace Museum and @norwoodsociety.co.uk, and will also have a table of models and freebies.

11:30-3pm, inside the Crystal Palace Bowl Concert Platform. Tickets:

www.eventbrite.co.uk/e/festival-o...

2/2

What car are you currently driving..?

just seen this - incredible! Will reskeet tomorrow ❤️