Europan Clock and Calendar

classic Classic list List threaded Threaded
7 messages Options
Reply | Threaded
Open this post in threaded view
|

Europan Clock and Calendar

Ron Hale-Evans
New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.

--
Ron Hale-Evans ... http://ron.ludism.org
Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

Amos Shapir-2
Hi Ron and calendar people,

I assume these 28 hours are Earth hours?  The page should be explicit about that.  It's also not clear if euday is relative to Jupiter or the Sun.  (It seems that both types of days may be useful for people inhabiting Europa)

And while we're at it, why not define an euclock as well?

Have fun,

Virus-free. www.avg.com

On Mon, Oct 2, 2017 at 2:54 AM, Ron Hale-Evans <[hidden email]> wrote:
New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.

--
Ron Hale-Evans ... http://ron.ludism.org



--
Amos Shapir
 
Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

Karl Palmen

Dear Amos, Ron and Calendar People

 

Europa’s rotation is locked to its orbit around Jupiter hence its day is equal to its orbital period around Jupiter.

See https://en.wikipedia.org/wiki/Europa_(moon)#Orbit_and_rotation Therefore the euday has to be defined relative to the sun, because Jupiter is fixed in the Europan sky.

 

The year has a 4332.59/3.551181 = 1220.042… sidereal days and therefore 1219.042… actual days.

 

The calendar puts 12*51*6/3 = 1224 Europan days in a Jovian year, which is 5 too many. Leap years are not mentioned and would be rare (about 1 in 24).

 

In the section about How To Notate Dates a euclock is implicit. Perhaps, with euhours equal to 1/28 euday or 1/84 of a Europan day. Perhaps, the Europan day could be divided into 3.5 Eudays of just over 24 hours each with exactly 24 euhours. The euweek would have exactly 7 eudays.

 

The actual Europan day is about 3.554094… earth days, which is longer than the sidereal day of 3.551181 earth days. The euhour would thus last about 1 hour 55.64 seconds.

 

My inclination is for a calendar similar to the French Republican calendar with a ‘year’ of 12 ‘months’ of 100 Europan days each and 19 epagomenal Europan days. Each ‘month’ would last just a little more than an Islamic year on earth. The calendar would be semi-perennial with respect to the euweek. Also about once every 24 ‘years’ a leap day is added to the 19 epagomenal days.

 

Karl

 

16(14(12

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Amos Shapir
Sent: 02 October 2017 07:39
To: [hidden email]
Subject: Re: Europan Clock and Calendar

 

Hi Ron and calendar people,

I assume these 28 hours are Earth hours?  The page should be explicit about that.  It's also not clear if euday is relative to Jupiter or the Sun.  (It seems that both types of days may be useful for people inhabiting Europa)

 

And while we're at it, why not define an euclock as well?

Have fun,

 

Virus-free. www.avg.com

 

On Mon, Oct 2, 2017 at 2:54 AM, Ron Hale-Evans <[hidden email]> wrote:

New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.

--

Ron Hale-Evans ... http://ron.ludism.org




--

Amos Shapir

 

Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

clifford emeric

Noon it is. 


Cheers Cliff



From: East Carolina University Calendar discussion List <[hidden email]> on behalf of Karl Palmen <[hidden email]>
Sent: Monday, October 2, 2017 5:02 AM
To: [hidden email]
Subject: Re: Europan Clock and Calendar
 

Dear Amos, Ron and Calendar People

 

Europa’s rotation is locked to its orbit around Jupiter hence its day is equal to its orbital period around Jupiter.

See https://en.wikipedia.org/wiki/Europa_(moon)#Orbit_and_rotation Therefore the euday has to be defined relative to the sun, because Jupiter is fixed in the Europan sky.

 

The year has a 4332.59/3.551181 = 1220.042… sidereal days and therefore 1219.042… actual days.

 

The calendar puts 12*51*6/3 = 1224 Europan days in a Jovian year, which is 5 too many. Leap years are not mentioned and would be rare (about 1 in 24).

 

In the section about How To Notate Dates a euclock is implicit. Perhaps, with euhours equal to 1/28 euday or 1/84 of a Europan day. Perhaps, the Europan day could be divided into 3.5 Eudays of just over 24 hours each with exactly 24 euhours. The euweek would have exactly 7 eudays.

 

The actual Europan day is about 3.554094… earth days, which is longer than the sidereal day of 3.551181 earth days. The euhour would thus last about 1 hour 55.64 seconds.

 

My inclination is for a calendar similar to the French Republican calendar with a ‘year’ of 12 ‘months’ of 100 Europan days each and 19 epagomenal Europan days. Each ‘month’ would last just a little more than an Islamic year on earth. The calendar would be semi-perennial with respect to the euweek. Also about once every 24 ‘years’ a leap day is added to the 19 epagomenal days.

 

Karl

 

16(14(12

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Amos Shapir
Sent: 02 October 2017 07:39
To: [hidden email]
Subject: Re: Europan Clock and Calendar

 

Hi Ron and calendar people,

I assume these 28 hours are Earth hours?  The page should be explicit about that.  It's also not clear if euday is relative to Jupiter or the Sun.  (It seems that both types of days may be useful for people inhabiting Europa)

 

And while we're at it, why not define an euclock as well?

Have fun,

 

Virus-free. www.avg.com

 

On Mon, Oct 2, 2017 at 2:54 AM, Ron Hale-Evans <[hidden email]> wrote:

New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.

--

Ron Hale-Evans ... http://ron.ludism.org




--

Amos Shapir

 

Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

Irv Bromberg
In reply to this post by Ron Hale-Evans
Quoting from the Wikipedia page about Europa:

"The radiation level at the surface of Europa is equivalent to a dose of about 5400 mSv (540 rem) per day,[40] an amount of radiation that would cause severe illness or death in human beings exposed for a single day.[41]"

It doesn't seem as if there will be any need for a calendar on the surface of that moon. There may be life in the subsurface ocean, assuming that life there is protected from the surface radiation, but if so it wouldn't have any ability to detect any celestial objects, so all that they might need are timekeeping devices.

-- Irv Bromberg, Toronto, Canada


From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Ron Hale-Evans [[hidden email]]
Sent: Sunday, October 01, 2017 19:54
To: [hidden email]
Subject: Europan Clock and Calendar

New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.
Ron Hale-Evans ... http://ron.ludism.org
Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

Ron Hale-Evans
In reply to this post by Ron Hale-Evans
Thanks to everyone for the feedback -- more than I had hoped for. I'll digest it and get back to you.

Ron

On Sun, Oct 1, 2017 at 4:54 PM, Ron Hale-Evans <[hidden email]> wrote:
New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.

--
Ron Hale-Evans ... http://ron.ludism.org



--
Ron Hale-Evans ... http://ron.ludism.org
Reply | Threaded
Open this post in threaded view
|

Re: Europan Clock and Calendar

Amos Shapir-2
In reply to this post by Irv Bromberg
Hi Irv and calendar people,

Even if people never get to Europa themselves, such a calendar will be needed by the people who will operate robots there.

See for example NASA's Earth-Mars Calendar https://mars.nasa.gov/files/resources/Mars-Exploration-Rovers-Calendar-2017_to_2018.pdf which is used by their "Martians".


On Mon, Oct 2, 2017 at 7:01 PM, Irv Bromberg <[hidden email]> wrote:
Quoting from the Wikipedia page about Europa:

"The radiation level at the surface of Europa is equivalent to a dose of about 5400 mSv (540 rem) per day,[40] an amount of radiation that would cause severe illness or death in human beings exposed for a single day.[41]"

It doesn't seem as if there will be any need for a calendar on the surface of that moon. There may be life in the subsurface ocean, assuming that life there is protected from the surface radiation, but if so it wouldn't have any ability to detect any celestial objects, so all that they might need are timekeeping devices.

-- Irv Bromberg, Toronto, Canada


From: East Carolina University Calendar discussion List [[hidden email]] on behalf of Ron Hale-Evans [[hidden email]]
Sent: Sunday, October 01, 2017 19:54
To: [hidden email]
Subject: Europan Clock and Calendar

New clock/calendar system for Europa, a moon of Jupiter.

http://www.ludism.org/tinfoil/Europan_Clock_and_Calendar

Comments, debugging welcome.
Ron Hale-Evans ... http://ron.ludism.org



--
Amos Shapir