Galactic Tick Day – A celebration of our progress around the milky way

[Tepix]

Interesting idea to use a unit that is universal to our galaxy. However, using deci-arcseconds (1/360/360/1000) seems arbitrary - it depends on the 360 degrees of a full circle and the decimal system.

Perhaps dividing the time period of 225million years by a power of two would be more universal.

For our life span, 2^27 looks good:

225.000.000 years / 2^27 = 1.67638 years, 611 days

Or perhaps 2^28? That'd be 305.94 days

[skissane]

I agree that divisions of 2^27 or 2^28 are in a sense less arbitrary than deci-arcseconds – but while the base (2) seems non-arbitrary, the same can't be said for the exponent (27 or 28). Wouldn't 2^32 be even better? A bit over 19 days.

Or I would argue 2^16 is even less arbitrary than 2^32. 2^(2^(2^2)) feels less arbitrary to me than 2^(2^5). A bit over 3,433 years.

This gives me an idea – write dates/times in hexadecimal. The first four hexits refer to units of 2^16 (roughly 3,433 years). The next four hexits refer to units of 2^32 (roughly 19 days). Then come units of 2^48 (roughly 25 seconds). Then units of 2^64 (about 385 microseconds), etc. However, you need to pick an epoch (zero point), and any choice of epoch is going to feel much more arbitrary than the system as a whole.

[adrianratnapala]

It's not universal anyway. Different stars orbit at different periods. The difference might not be large, but I am not sure you can really define a "galactic year" with much precision.

[al_biglan]

Agreed this is arbitrary. Why not divide into 2*pi units and divide from there. Been a long time since I touched orbital stuff, but maybe add a "normalization" that factors in the Kepler area carved out by an object in orbit around the galactic center (tho... I'm not sure how well Kepler works in the galactic rotation sense... but something similar perhap?) In any case, if the orbit isn't circular, something would need to adjust for the change in relative angular rotation.

Also... may want to standardize on reporting this in terms of "seconds" and dropping "days" and other locally referenced time measures :-)

[InclinedPlane]

An arcsecond is 1/360/60/60 of a circle (1/360/3600), a deci-arcsecond is one tenth of that.

[tehrei]

That's not really any more or less arbitrary.

[BetaCygni]

The definition is very arbitrary: a centi-arcsecond. Why not celebrate a galactic quarter second every 704 days? Just as arbitrary, but much more relatable. As starting point, just take the year 0, so we're living at 4 galactic minutes and 21.25 seconds now.

[thaumasiotes]

The year 0?

[givan]

What if our sun is not an exception?

Pluto turns around the Sun, but from Pluto the Sun is very small. Idem, the Sun could turn around a very big and very far star looking very small from the Earth.

We could be in a wide binary where currently the stars are at a maximum opposites, then the binary companion would be a very bright star at night, and not visible during the day.

This could explain the nemesis star theory for mass extinctions https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star) and also the recently discovered anomaly in the planets orbit https://www.caltech.edu/news/caltech-researchers-find-eviden... or why the Kuiper Belt ends suddenly or the Pioneer anomaly or maybe even the Oort Cloud.

There are some still unproved theories that state this star could be Sirius binary and we are in fact in a triple star system.

[restalis]

It would be interesting to relate the galactic revolution subdivisions with other neutral units like multiples of Planck time. Like others mentioned here, the "tick" is very cultural and therefore not assured to be accepted in the long term by future generations (of our more rational off-springs).

[bryondowd]

Interesting thought. Tough to get to anything useful from Planck time though. 2^^8 (as in 2^2^2^2^2^2^2^2) Planck times would be a bit over 30 microseconds, but then I'm not sure how you'd go from there to a useful time scale.

[jankor]

Well you can check your Galactic Tick birthdays http://jankor.github.io/galacticbday/

If you feel too Sun-centric.

[jbverschoor]

Just in time to play Galactic Escape - escape black hole :)

https://itunes.apple.com/app/apple-store/id1076368667?pt=132...

Sorry for the plug :)

[sizzzzlerz]

Already? Seems like the time between them keeps getting shorter every year! I haven't even started my shopping yet.

[jupp0r]

Oh no, galactic ticks are going to drink all of our blood!!!!

SCNR

[throwaway000002]

Um, as the Earth to the Sun, what's the length of the Sun's day with respect to the galactic center.

If my knowledge of mechanics is correct, given enough time, all days tend to infinity? (Like the moon's day with respect to Earth?)

[Tepix]

Not sure what you mean, but according to https://en.wikipedia.org/wiki/Solar_rotation "at the equator the solar rotation period is 24.47 days and almost 38 days at the poles".