Search found 21 matches

by sla29970
Fri Aug 01, 2014 2:46 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1402: "Harpoons"
Replies: 41
Views: 22242

Re: 1402: "Harpoons"

In my opinion the stinger used on STS-51-A counts as a harpoon, but perhaps considerations about how it was used prevent such acknowledgement.
by sla29970
Mon Jul 01, 2013 2:43 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

During the second chirp 14 Andromedae winked out.
by sla29970
Mon Jul 01, 2013 12:58 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

sla29970 wrote:
sla29970 wrote:In the frame after the ch*rp (that's 2467)T Piscium has vanished.

And in 2468 T Piscium is back again.

Make that tau Piscium. Also, during the same frame pi2 Pegasi winked out.
by sla29970
Sun Jun 30, 2013 11:07 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

sla29970 wrote:In the frame after the chirp (that's 2467)T Piscium has vanished.

And in 2468 T Piscium is back again.
by sla29970
Sun Jun 30, 2013 10:45 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

In the frame after the chirp (that's 2467)T Piscium has vanished.
by sla29970
Sun Jun 30, 2013 7:19 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

I hope we get to see the Andromeda galaxy. It should be visible in a couple more frames. But the Moon is full, so maybe not. Actually, with a full Moon, I'm surprised we're seeing as many stars as we are. Then again I'm a city-boy and don't have a lot of experience with full Moons in dark skies. It...
by sla29970
Sun Jun 30, 2013 3:53 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

if drawn with astronomical accuracy the moon will look like a comically tiny dot, smaller than Cueball's head. And with Randall aware that we're here putting our calipers on everything, I won't be too surprised if he just throws up his hands and leaves it out. I am still getting used to this greysc...
by sla29970
Sun Jun 30, 2013 3:41 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

if drawn with astronomical accuracy the moon will look like a comically tiny dot, smaller than Cueball's head. And with Randall aware that we're here putting our calipers on everything, I won't be too surprised if he just throws up his hands and leaves it out. I am still getting used to this greysc...
by sla29970
Sun Jun 30, 2013 3:13 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

This is, of course, assuming that the moon is still there, for if not, then the rate of precession will be greatly reduced, and also the leap seconds. But if the moon is still there then 13291-04-10 is around full moon, so the moon has been up all night, and that would explain why it has never been...
by sla29970
Sun Jun 30, 2013 2:43 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

I agree with this. To rephrase the sidd's first paragraph, the calendar date might work out to October, but the season is spring. That's one of the things precession does, is cause the seasons to shift around the calendar. So the night will be shorter than 12h. Nothing can be said about what calend...
by sla29970
Sat Jun 29, 2013 6:44 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

it is possible to work out how much the seasons have rotated. by my calculations, it is roughly equivalent to 9th October, so mid Autumn in the northern hemisphere. The design of the Gregorian calendar is to keep the vernal equinox on March 21. Although not perfect it will do so to within a couple ...
by sla29970
Fri Jun 28, 2013 5:03 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

For the non-astronomically-informed, what's a precession cycle? http://en.wikipedia.org/wiki/Axial_precession_(astronomy) and it is extraordinary hubris to presume that any calendar will be in use for more than 1000 years, so I am avoiding the names of months and choose to specify time of year by t...
by sla29970
Fri Jun 28, 2013 4:21 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Time"

Actually, it's kind of necessary for the sun to be setting (and therefore, because the sun set near the horizontal center of the frame, for the camera to be facing) south of west. That's because it must be around November for the sun to be in or near the constellation Scorpius, and in November the ...
by sla29970
Sun Mar 31, 2013 9:10 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1190: "Time"
Replies: 107280
Views: 50349089

Re: 1190: "Thing that keeps slippin' (slippin', slippin'( in

Smithers wrote:We could wield pixels as an unit of length, but then we need to decide whether to wield pixels before or after the great expansion.


I think the merlon should be the unit of length, invariant of the scale change.
by sla29970
Fri Jan 04, 2013 7:34 pm UTC
Forum: What If?
Topic: What-If 0026: "Leap Seconds"
Replies: 79
Views: 27965

Re: What-If 0026: Leap Seconds

Why use UTC to define anything except time of day? ... Some standards committee releases the coefficients. This is already possible to the current level of precision. See http://www.ucolick.org/~sla/leapsecs/right+gps.html but note that implementing it requires significant effort that violates exis...
by sla29970
Wed Jan 02, 2013 2:34 pm UTC
Forum: What If?
Topic: What-If 0026: "Leap Seconds"
Replies: 79
Views: 27965

Re: What-If 0026: Leap Seconds

I'm sure the people seriously advocating dropping leap seconds just believe they cause more problems then they fix. Yet those delegates have not acknowledged that there are other delegates representing countries whose position is that the word "day" should remain a concept that is related...
by sla29970
Wed Jan 02, 2013 7:20 am UTC
Forum: What If?
Topic: What-If 0026: "Leap Seconds"
Replies: 79
Views: 27965

Re: What-If 0026: Leap Seconds

You would need to have a "terrestrial second" that is synchronized with the Earth, while retaining the "scientist's second" that is invariant Which is exactly what we do have now. POSIX requires that there be 86400 seconds in a day, and also that a day be a mean solar day of Uni...
by sla29970
Tue May 29, 2012 8:03 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1061: "EST"
Replies: 128
Views: 44671

Re: 1061: "EST"

The difference is that zoneinfo has to be updated regularly in order for the computer to stay correct. Getting that to happen dynamically is what TC TIMEZONE is all about. Read further http://calconnect.org/tc-timezone.shtml as they get close to a mechanism which can serve all the arbitrary bureauc...
by sla29970
Mon May 28, 2012 3:23 pm UTC
Forum: Individual XKCD Comic Threads
Topic: 1061: "EST"
Replies: 128
Views: 44671

Re: 1061: "EST"

There is a simple system available to provide consistent time all around the world. Set an arbitrary beginning point and then count seconds. The size of a second is also arbitrary but you can use a second that is in common use. Even if we disregard the legal systems of the world, two IEEE standards...
by sla29970
Mon May 28, 2012 7:05 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1061: "EST"
Replies: 128
Views: 44671

Re: 1061: "EST"

There's a simple way of sorting out the leap second issue in UTC. Modify NTP to transfer a table of known and historical leap seconds. Update time functions in operating systems, basing them on the routines in the International Astronomical Union's SOFA library (pdf): Much simpler to move the leap ...
by sla29970
Thu Dec 04, 2008 5:29 am UTC
Forum: Science
Topic: Physics: is the earth's rotation slowing down?
Replies: 19
Views: 3478

Re: Physics: is the earth's rotation slowing down?

Observations made by rocks and fossils (paleorotation) show the slowing has been happening for 3 billion years. Observations made by humans show the slowing for the past 3000 years.

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