A Changing Landscape

A tale of two lava lakes, of a landscape altered in way so dramatic it is hard to comprehend.

We think of solid rock being the ultimate in permanency, something about the world that should never change, at least in the span of a few months. Geologic change takes thousands of years, not less than one, it just seems wrong when this rule is violated.

Places we once stood, or parked a car, a hiking trail across a plain of solid rock… All gone in a dramatic upheaval. A parking lot the lies upon a block of rock the size of a supertanker, sitting hundreds of feet below where I once parked the car. Change is the reality of an active volcano.

The glow from a lava lake in Halemaʻumaʻu lights the clouds prior to the May 2018 eruptions
The glow from a lava lake in Halemaʻumaʻu lights the clouds prior to the May 2018 eruptions

I have seen change on this scale once before when Mt. St. Helens removed a mountain top that stood upon the horizon of childhood memory. Here at Kilauea the change was a bit slower, but no less dramatic.

I look across that caldera and note the places that are the same, the places that are gone. I may understand what has happened and how, but still some parts of my mind insist that this just cannot be true… Solid rock should not disappear or crumble like a cookie.

The glowing pit of Halemaʻumaʻu with the new lava lake
The glowing pit of Halemaʻumaʻu with the new lava lake

The return of lava to the crater seems like a return of normalcy. There was lava here for years, there should be lava here. Perhaps the lava will cover over that yawning pit that should not be. Fill the yawning chasm that affronts my senses so.

Perhaps, if the crater continues to fill, flooded to the rim with new lava, a new caldera floor will form, the cycle complete. Perhaps it may be possible to once again walk across the floor of Kilauea Caldera.

An Extra Second

Today will be 86,401 seconds long. That number may seem odd, particularly when you consider that most days are 86,400 seconds long. The difference is a result of the leap second being added to our clocks at the end of June 30, 2015 at 23:59:59.

Observatory Clocks
Two new GPS time servers installed in the Keck 2 computer room
The need for an extra second comes from the irregular rotation of our planet. Due to gravitational interaction with the Moon our planet is gradually slowing its rotation. Other shifts can also cause slight irregularities in the planetary rotational rate. In order to keep Coordinated Universal Time in phase with the Earth’s rotation it is necessary to insert an extra second every so often when the error becomes too large.

Since zero hours universal time occurs at 14:00 Hawaii Standard Time, this extra second will occur at 2pm in the afternoon for my readers in the islands. If you are watching a clock that can account for this leap second you will see this second appear. The clock can do a few things, it could simply stop for a second, holding at 23:59:59 for two seconds. The clock could also count the extra second, displaying 23:59:60.

Update: A small group of true nerds gathered in the Keck 2 computer room at 0hUT today and watched our timeserver do leap second. The display notably remained at 23:59:59 for two seconds.

Generally only high precision time servers and GPS receivers will contain software to correctly implement the leap second. Most clocks do not correct for leap seconds, it is just not that important that this feature be implemented perfectly in most devices.

Network connected clocks will simply adjust the time on the next opportunity. Connected clocks routinely synchronize with an online time standard. Your computer requests the correct time via NTP protocol from an internet time server once each day, this is the usual default configuration for a net connected computer unless you have changed it. Cell phones get their time from the network and may receive their extra second more quickly, maybe within a few moments of the leap.

The rest of the clocks in your life are usually more than a few seconds off in any case.

Last time this occurred in 2012 there were some troubling software crashes around the world. Airline departures were delayed and some major websites went down. There is some concern that similar occurrences may occur this time. As a result some experts have argued to do away with leap seconds and just let the error accumulate. The argument rages and we may see leap-seconds abolished, in the meantime this one will occur.

Now that you know about it, enjoy your extra second today. Remember to watch that clock at zero hours universal time and see what happens.

On Time Again

So last month the observatory clocks decided is was 1995. A software bug interfered with proper decoding of the GPS time signal. For a few weeks we got by by kludging two of the old clocks together in a creative way to provide good time for the telescopes.

The new clocks are now fully online and operational. I ran one of the new time servers for a couple weeks while keeping the old time servers in place as a backup. These have now been removed, with a second new unit installed as an in-place spare.

Hopefully this will keep everything on-time for the foreseeable future. Two new precision clocks, Microsemi SyncServer S350’s, time accurate to microseconds.

Meantime there may be a fix for the old equipment, a new GPS module by Heol Design. We have one on order to try. It would be a shame to throw out these very nice clocks.

Observatory Clocks
Two new GPS time servers installed in the Keck 2 computer room

A Matter of Time

Time… It is simply a matter of time. At 00:00UT May 3rd, many of the observatory computers suddenly started reporting that the date was September 17th, 1995. To say that this created some problems is a dramatic understatement.

Datum TS2100 Time Servers
Two Datum TS2100 time servers installed above the telescope drive control computer (TDC)

The problem came from the primary observatory clock. This clock, properly called a time server, uses GPS signals to create a time reference that is accurate to microseconds. This is made possible by referencing to the atomic clocks carried by each GPS satellite. A time server is intricately connected to the network to distribute this time. Any computer in the building can ask it for time via the NTP protocol, but that has some inaccuracy due to network delays. For equipment requiring more precise time the server distributes a hard wired time reference using the IRIG-B protocol or a 1PPS timing pulse.

Without accurate time a telescope will simply not point in the correct direction. The calculation that the computers perform must take into account our rotating planet. Feed incorrect time to that calculation and you will point to the wrong piece of sky. A few milliseconds off can result in a pointing error of arcseconds, a large error for a large telescope.

Continue reading “A Matter of Time”

Creationist Astronomy

Astronomy is a science where human timescales become insignificant. It seems like everything we are watching takes millions or even billions of years to occur. To be sure, there are a few things that happen quickly, like supernovae, but those events are the exceptions. Everywhere we look we see the stately dance of stars and galaxies, the formation of worlds. The dance is spread across distances and times so vast that even those who study the universe have difficulty comprehending the sheer immensity involved. Stars and planets take hundreds of thousands of years to form, a galaxy collision may go on for millions of years.

M6 The Butterfly Cluster
M6, the Butterfly Cluster
And yet there is a significant portion of our fellow citizens who insist that the universe is only a few thousand years old. I encounter this belief all too often, a dogged insistence that everything was created just a few thousand years ago. There are variations on the theme, with differing numbers, but these beliefs generally accept that our universe and the Earth were formed within the last ten thousand years. Never mind we have literally mountains of evidence to the contrary, when that evidence clashes with worldviews instilled since birth by a religion and parents, a discouraging number of people ignore reality and cling to what they were taught. To admit otherwise would open up too many other dearly held beliefs to questioning, a truly uncomfortable challenge.

Continue reading “Creationist Astronomy”

Transit of Venus Timing

Transit of Venus
The June 2004 Transit of Venus, image credit Jan Herold
For reference I am posting precise transit timing for the June 5th Transit of Venus. The data is taken from Fred Espenak’s wonderful NASA Eclipse Website. I just extracted the cities that are of most interest to my Hawaiian readers. For the full list of US cities you can go here.

As you might notice, the times change by a mere two seconds between Kona and Honolulu. These times will be pretty close for the entire island chain. That last number is the Sun’s altitude, the angle above the horizon. Note that this is near 90° for Hawai’i, nearly straight up for the start of the event. Final contact will occur with an altitude of about 5°, just above the horizon near sunset.

Location Name External Sun
Ingress Alt

h m s °
Internal Sun
Ingress Alt

h m s °
Greatest Sun
Transit Alt

h m s °
Internal Sun
Egress Alt

h m s °
External Sun
Egress Alt

h m s °
Anchorage, AK 14:06:30 51 14:24:04 51 17:26:53 38 20:30:46 16 20:48:32 14
Honolulu, HI 12:10:07 85 12:27:46 89 15:26:20 49 18:26:38 9 18:44:38 5
Kona, HI 12:10:09 86 12:27:48 87 15:26:16 47 18:26:33 7 18:44:33 3
Los Angeles, CA 15:06:26 58 15:24:02 55 18:25:33 18 — – — –
Phoenix, AZ 15:06:03 54 15:23:40 50 18:25:32 13 — – — –
Portland, OR 15:06:05 57 15:23:40 54 18:25:53 23 — – — –
San Francisco, CA 15:06:29 61 15:24:04 57 18:25:39 22 — – — –
Seattle, WA 15:05:58 56 15:23:32 53 18:25:57 23 — – — –

All times are local time. Keep in mind that this event occurs on June 5th for viewers in the US and Hawai’i. Some sources show June 6th for a date, and so it will be for viewers on the other side of the date line in Australia, Japan and China.