1,210 reputation
721
bio website dotancohen.com
location
age 36
visits member for 3 years
seen 2 hours ago

Oct
24
asked Maximum resolution per lens size
Oct
12
comment Lowest gravity on Earth's surface?
Thank you Dimuthu!
Oct
12
accepted Lowest gravity on Earth's surface?
Oct
12
accepted Gas pressure equalisation: Where does the excess energy go?
Oct
2
comment Will a hole cut into a metal disk expand or shrink when the disc is heated?
This is analogous to the reason that the holes in cookies get smaller, not larger, when baked.
Oct
2
answered Does Earth's rotation change at a constant rate?
Oct
2
comment Gas pressure equalisation: Where does the excess energy go?
Thanks John. The microscopic explanation of the gas molecules' speed was quite what I was missing. If Zephyr doesn't write back as an answer then I'll accept this one.
Oct
1
asked Gas pressure equalisation: Where does the excess energy go?
Sep
21
awarded  Custodian
Sep
17
comment Do any naked-eye stars have planets
Thanks. I did know that some doubt had been shed on the existence of the planet.
Aug
17
comment How empty of fuel are spacecraft booster rockets typically?
Thank you. You briefly mention a safety factor of 1.1. Does that mean that roughly 9% of the launch fuel remains?
Aug
17
revised How empty of fuel are spacecraft booster rockets typically?
added 4 characters in body
Aug
17
asked How empty of fuel are spacecraft booster rockets typically?
Aug
10
awarded  Yearling
Jul
31
comment Does Earth have a code name?
I think that the font issues are due to your browser, not the site: ⊕
Jul
30
revised Will Pluto be in the ecliptic plane when New Horizons passes by? Was this deliberate?
edited title
Jul
24
answered Gas Cylinder Life
Jul
24
comment How did Cook and other astronomers time the 1769 Venus transit?
Land-based longitude had its own set of problems, mainly how to transport the clocks (not a problem for Cook). Land navigation was done using Lunar methods even after the seafarers switched to clocks.
Jul
23
comment How did Cook and other astronomers time the 1769 Venus transit?
Actually, longitude was not well-known in the 18th century. I understand that specifically Tahiti's longitude was known, that is why Cook went there. But even measuring high-noon would not be very precise.
Jul
22
comment How did Cook and other astronomers time the 1769 Venus transit?
@dmckee: Thank you for that excellent link! That does suggest that perhaps the lunar distance method was used.