Tag Archives: jupiter

The Sun Ain’t Gonna Shine (Anymore) – Maybe. Polar Exploration and the Mysterious Novaya Zemlya Effect

Sun's image distorted and elongated by atmospheric refraction ©Tim Jones
Sun’s image distorted and elongated by atmospheric refraction ©Tim Jones

A Polar Phenomenon

In May 1915, as Ernest Shackleton and the crew of Endurance entered their fourth month trapped in ice on the Antarctic’s Weddell Sea, the ship’s navigator added to the gloom by declaring the Sun would be absent from the sky for the next seventy days.   You expect this at above 75° South; but then on the 8th of May something strange happened.  The Sun reappeared – several times:

The sun, which had made “positively his last appearance” seven days earlier, surprised us by lifting more than half its disk above the horizon on May 8.  A glow on the northern horizon resolved itself into the sun at 11 a.m. that day.  A quarter of an hour later the unseasonable visitor disappeared again, only to rise again at 11.40 a.m., set at 1 p.m., rise at 1.10 p.m.. and set lingeringly at 1.20 p.m.

Ernest Shackleton, 19151

 

Shackleton understood the effects of atmospheric refraction, that temperature and density differences can bend light – especially near the horizon.   At sunrise and sunset the disk of the Sun can appear distorted: lengthened or flattened, or displaced from its true position in the sky – where Newton put it.

Endurance in Weddell Sea
Ernest Shackleton made his observations from the Endurance while frozen in the Weddell Sea (the bay top left)

Mariners knew about the phenomenon, and referenced standard refraction tables to correct sextant readings in navigation; but the system broke down below about 6 degrees, where refraction increased rapidly and non-linearly.

How atmospheric refraction can make the Sun visible when it's still below the horizon ©Tim Jones
How atmospheric refraction can make the Sun visible when it’s still below the horizon ©Tim Jones

In this case, as Shackleton recorded in his journal, the Sun was 2 degrees and 37 minutes (2°37′) from its true position, 2 degrees more than any refraction table prediction.  Plotting position from this observation would place the Endurance 120 miles from its actual location.

What Shackleton experienced was an extreme case of atmospheric refraction known as the Novaya Zemlya effect, first reported in 1597 by Gerrit De Veer2 , one of the crew on Willem Barent’s third voyage to discover a north-east passage.  Obliged to hunker down for the polar winter in a safety hut or ‘Het Behouden Huijs‘ built on the Novaya Zemlya island chain north of Russia, De Veer reported the return of the post-winter Sun a whole two weeks before it should have been visible; it was in fact 5°26’ below the horizon.  The same thing happened two days later, the Sun still, by the book,  4° below the horizon.

Novaya Zemlya
Map depicting Willem Barents three voyages to discover a North East Passage, showing the Novaya Zemlya islands (Wikipedia)

novaya1The Novaya Zemlya effect occurs in Arctic regions where tracts of cold air remain uniquely stable over hundreds of kilometers, creating a special instance of a  meteorological temperature inversion.  The distortion, powerful enough to bend light through four or five degrees, can make celestial bodies like the Sun or Moon appear wholly above the horizon when they are physically below it.  (If you imagine looking at the horizon, five degrees is the same as ten Suns or Moons in a row.)

For hundreds of years, Gerrit De Veer’s solar observations, and equally his report of a curiously displaced conjunction of the Moon and Jupiter, were not believed.  They said he must have counted the days wrong, or used the wrong sort of calendar.  It took the corroborating reports of polar explorers like Shackleton and, as recently as 2003, ray-tracing simulations3 using contemporary atmospheric data, to vindicate De Veer fully.

Modern almanacs still include refraction tables. (HM Nautical ALmanac Office)
Modern almanacs still include refraction tables. (HM Nautical ALmanac Office)

 

Time Travel with Starry Night

I’ve set up my own simulations of the celestial events reported by Shackleton and De Veer using the planetarium software Starry Night.  The program can’t reproduce the ray traced refraction effects modeled by van der Werf et al3 – whose validity I’m not equipped to comment on by the way, but it’s still satisfying to check the published numbers and get a feel for what the events looked like all those years ago.

 

 

 

 

Shackleton’s Solar Observation

First up, the view from the Endurance in 1915:

View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT) ©Tim Jones, Starry Night Software
View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT) ©Tim Jones, Starry Night Software

The horizon terrain here is generic Starry Night; apart from being icy-white, the true horizon would run perpendicular to and cross the graduated white Meridian line at zero (0) degrees.  The green line is the Ecliptic.  Things are clearer for our purposes, if less romantic, if we turn off the daylight effect and fancy terrain and zoom in a bit.  It’s now clear the Sun was below the horizon when Shackleton reported seeing it: i.e. with reference to the Meridian on the left, the Sun looks about two and half degrees below the zero degree mark (Shackleton’s 2°37′):

shackleton-120
View from Weddell Sea (Lat. 75 degree 23 mins S Long. 42 degree 14 mins W) 8th May, 1915, 1:20pm (UT). With generic landscape and daylight effect turned off ©Tim Jones, Starry Night Software

 

Gerrit De Veer’s Solar Observation

Willem Barent’s crew, marooned 300 years earlier at the opposite end of the planet, made their observations from the ‘Behouden Huijs‘ at coördinates 76° 15.4′ North 68°18.6’ East, Novaya Zemlya.  This view from the Huijs at 7 o’clock on the morning of 24th January 1597, shows the Sun was firmly below the horizon when Gerrit De Veer observed it – a whole 5°26′ below (horizon is perpendicular to the zero mark on the white Meridian line, green line is the Ecliptic):

Gerritt De Veer sunrise
View from the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) 24th Jan, 1597, 7:00 am (UT). ©Tim Jones, Starry Night Software

 

Gerrit De Veer’s Moon-Jupiter Conjunction

The Moon-Jupiter conjunction reported by De Veer physically happened at 0:14 UT on 25th January 1597 (there is a small error in the 0:24 UT time given in the contemporary tables by Scala that De Veer used).   Like astronomers today, De Veer identified the moment of conjunction as the time when a line drawn along the shadow separating light from dark on the moon’s surface, the terminator, pointed directly at Jupiter, as in this photograph I took of the Moon-Jupiter conjunction of 21 January 2012:

Moon and Jupiter, 18:45, 21.01.2012, Los Angeles ©Tim Jones
Moon and Jupiter, 18:45, 21.01.2012, Los Angeles ©Tim Jones

 This is the Starry Night simulation of the De Veer conjunction:

De Veer's moon jupiter conjunction
Moon-Jupiter conjunction, 0:14 (UT) 25th Jan,1597. Location: the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) ©Tim Jones, Starry Night Software

The Moon is barely above the horizon and Jupiter is below it (again, reference the zero on the white Meridian line).

Gerrit De Veer saw this view, but over an hour after it happened: i.e. at 01:27 UT not 00:14 UT.  As van der Werf’s analysis explains, De Veer reported the conjunction at 6 a.m. local time, which was 4:33 hours ahead of UT.  Such was the unbelievable power of the Novaya Zemlya effect to make this happen that few indeed believed it.   De Veer learned about the conjunction from his copy of the Ephemerides of Josephus Scala which gave times for Venice.  Here we pick up the story in De Veer’s own words and the spellings of his 1609 translator William Phillip:

Whereupon we sought to knowe when the same coniunction should be ouer or about the house where we then were; and at last we found, yt the 24 day January was the same day whereon the coniunction aforesaid happened in Venice, at one of the clocke in the night [= 1 in the morning of 25th Jan], and with vs in the morning when ye sun was in the east: for we saw manifestly that the two planets aforesaid approached neere vnto each other, vntill such time as the moone and Jupiter stood ouer the other, both in the sign of Taurus, and that was at six of the clocke in the morning;at which time the moone and Jupiter were found by our compas to be in coniunction, ouer our house..
Gerrit De Veer 1597

Yet ray tracing the scenario 400 years later, with Jupiter two degrees below the horizon and the Moon just above it at  conjunction, shows that atmospheric conditions raised Jupiter’s apparent position disproportionately to that of the Moon.  Moreover, the simulation reproduced what De Veer saw at the time he saw it: a conjunction visible to him at around 02:00 UT.  The ray tracing team made a further minor adjustment for the Equation of Time effect, which brought their estimate of when the conjunction was visible to De Veer as 06:20 local time, which is impressively close to his 06:00.)

Apparent position of Jupiter and the Moon after allowing for atmospheric refraction. Diagram reproduced from analysis by van der Werf et al, 2003 (reference 2)
Apparent position of Jupiter and the Moon after allowing for atmospheric refraction. Moon is double actual size for clarity. Diagram reproduced from analysis by van der Werf et al, 2003 (reference 3)

One More Thing

Although Gerrit De Veer’s vindication now seems complete, there was one little alarm bell went off during my research, and that concerns De Veer’s reference to both the Moon and Jupiter being in the constellation of Taurus at the time of conjunction.  Zooming in to see the 1597 conjunction against modern constellation boundaries puts it well into Aries.  So what gives?

constell
Modern constellation boundaries. Moon-Jupiter conjunction, 0:14 (UT) 25th Jan,1597. Location: the rescue hut on (Lat. 76 degree 15.4 mins N Long. 68 degree 18.6 mins W) ©Tim Jones, Starry Night Software

Maybe the constellation boundaries have changed; let’s have a look at Albrecht Dürer’s beautiful star chart from 1515.  The belly of the bull tucks a little further under the ram than in modern charts, but the conjunction is still firmly in Aries. 

Star chart of the northern skies, Albrecht Dürer, 1515, Nuremberg.
Star chart of the northern skies, Albrecht Dürer, 1515, Nuremberg.

Maybe the Moon made the stars in Aries harder to see that night, so instead De Veer focused on the sparkling Pleiades and Hyades clusters in Taurus; I’d probably do that if I were standing in a freezing Arctic wasteland staring at the sky at six in the morning.  I later discovered Charles Beke4 in a 19th century analysis of the William Phillip translation also noticed the discrepancy.  He points out a retrogression of the equinoctial points – the places where the celestial equator intersects the ecliptic – has since De Veer’s day shifted the positions of the constellations in terms of longitude and latitude relative to those references; but that rather suggests in his write-up De Verre placed the conjunction in whatever constellation the numbers dictated, rather than where he saw it?  Still a bit of a mystery to solve then – at least in my mind.  

References

  1. E. Shackleton, South: The Story of Shackleton’s Last Expedition 1914–1917, MacMillan, New York, 1920
  2. Gerrit De Veer, The Three Voyages of William Barents to the Arctic Regions (1594, 1595 and 1596). London, 1876 (translation of 1609 original).
  3. Gerrit de Veer’s True and Perfect Description of the Novaya Zemlya Effect, 24-27 January 1597, Siebren Y. van der Werf, Günther P. Können, Waldemar H. Lehn, Frits Steenhuisen, and Wayne P. S. Davidson; Applied Optics, Vol. 42, Issue 3, pp. 379-389 (2003)http://dx.doi.org/10.1364/AO.42.000379
  4. Charles T. Beke, The Three Voyages of Willem Barents to the Arctic Regions 1594, 1595 and 1596 by Gerrit de Veer, 2nd ed.William Phillip, trans., Hakluyt Society, London, 1876 (Page 147)

 

Venus, Jupiter, Mercury Conjunction 26th May 2013

Conjunction of Venus (right, low), Jupiter (left), and Mercury (top). 21.45 BST 26 May 2013 (Photo:Tim Jones)
Conjunction of Venus (right, low), Jupiter (left), and Mercury (top). 21.45 BST 26 May 2013 (Photo:Tim Jones)

This is one of the most convenient pictures of a conjunction I’ve ever taken.   I just opened the door of the flat, which has a reasonably clear view out to the West across the Thames, and there it was!

Like most folks, I hardly ever get to see Mercury at all – especially when I’m in the UK.  With Venus and Jupiter as markers, it’s easy to find.

I should add that Mercury wasn’t actually naked-eye visible tonight, but clear enough in 15×70 binocs, and through the magic of digital photography of course. (This was 1/8″, f5.6, ISO 320, 135mm.)

These three planets will be shuffling around the same patch of sky for the next few evenings, so if you didn’t catch them tonight, try again tomorrow.

Update 3rd June 2013

The three planets have all strung out by now.  Just Mercury visible in this shot.

Mercury, 3rd June 2013 (Photo:Tim Jones)
Mercury, 3rd June 2013 (Photo:Tim Jones)

 

 

 

Jupiter Conjunction with the Moon 21st January 2013

Jupiter this afternoon is moving in for the closest line-of-sight conjunction with the moon you’ll see until the year 2026.

Moon with Jupiter in daylight. 15.30 (PST) from Los Angeles. © Tim Jones
Moon with Jupiter in daylight. 15.30 (PST) from Los Angeles. © Tim Jones

Jupiter is very bright and easily viewable in the daytime – especially with binoculars; the problem is you can never find it.   Because it’s so close to the moon today, that’s no problem: find the moon and you’ve found Jupiter.  This is my first pic of the day.  I’ll update with new ones every few hours as Jupiter moves in to closest approach and the Jovian satellites start to appear.   I have only a reasonable telephoto with me, not a telescope, but we’ll see how it goes.

Get out there now with those binocs!

Moon with Jupiter in Daylight 16:30 (PST) Los Angeles ©Tim Jones
Moon with Jupiter in Daylight 16:30 (PST), 21.01.2013, Los Angeles ©Tim Jones
Moon with Jupiter 17:00 (PST) Los Angeles
Moon with Jupiter 17:00 (PST), 21.01.2013, Los Angeles ©Tim Jones
IMG_0499_2
Jupiter and Moon, 17:25 (PST) Los Angeles, ©Tim Jones
Jupiter and Moon, 17:45 (PST) Los Angeles. ©Tim Jones
Jupiter and Moon, 17:45 (PST) Los Angeles. ©Tim Jones
Jupiter and Moon, 17:55 (PST), 21.01.2013, Los Angeles. ©Tim Jones
Jupiter and Moon, 17:55 (PST), Los Angeles. ©Tim Jones
Jupiter & Jovian Moons, 17:55 (PST) ©Tim Jones
Jupiter & Jovian Moons, 17:55 (PST), 21.01.2013, Los Angeles, ©Tim Jones
Jupiter and Moon, 18:41 (PST) Los Angeles. ©Tim Jones
Jupiter and Moon, 18:41 (PST), 21.01.2013, Los Angeles. ©Tim Jones
Moon and Jupiter, 18:45, 21.01.2013, Los Angeles ©Tim Jones
Moon and Jupiter, 18:45, 21.01.2013, Los Angeles ©Tim Jones
Moon, Jupiter, Hyades & Pleiades clusters 18:49 (PST), 21.01.2013, Los Angeles. ©Tim Jones
Moon, Jupiter, Hyades & Pleiades clusters 18:49 (PST) Los Angeles. ©Tim Jones
You don't need the Hubble Space Telescope to have fun with the sky...
You don’t need the Hubble Space Telescope to have fun with the sky…
Moon and Jupiter, 19:21 (PST), Los Angeles. ©Tim Jones
Moon and Jupiter, 19:21 (PST), Los Angeles. ©Tim Jones
Position of Jovian moons 19:45 (PST) Starry Night software
Position of Jovian moons 19:45 (PST) Starry Night software (note: this just to show moon positions; the image of Jupiter here is from the software; my kit isn’t that good).
Jupiter and Moon, with the fairy-lights on and Orion rising. What more could you want?
Jupiter and Moon, with the fairy-lights on and Orion rising. What more could you want?

That’s about as close as it will get: 30 minutes of arc, or a Moon’s diameter.  Some folks in the Southern Hemisphere will see Jupiter completely disappear behind the moon – an occultation.  But that’s me done for the evening.  Happy stargazing!

Life, Talk To Me About Life

Search for Life at the Royal Institution
Search for Life at the Royal Institution (Photo Tim Jones)

I kind of expect to see demonstrations at the Royal Institution, an association with the Christmas Lectures I guess.

So it was nice to see a few props at Lewis Dartnell’s talk on astro-biology yesterday evening:  a Geiger counter, a jar of fluorescent quinine, a piece of Mars.   A piece of Mars !!! That got a reaction from the audience – along with an intelligent question – “how do you know it’s from Mars?”  As it happens, matching isotopes between the 1911 meteorite sample and material tested in-situ by the Viking lander on Mars leave little doubt about its origins.  Whether it contains signs of former Martian life, as some claim, is another matter.

Lewis Dartnell & Naomi Temple (Royal Institution) with the famous RI bench.  Photo: Tim Jones
Lewis Dartnell & Naomi Temple (Royal Institution) with the famous RI bench. (Photo Tim Jones)

The evening’s bottom line was that no extra-terrestrial life has yet been found; but there is particular hope for Mars and/or Jupiter’s moon Europa.

Dartnell structured his lecture from the Earth outwards: Earth, solar system, galaxy, etc.   With ‘Earth’ came a definition of life, and what an excuse that was to show some clips from this amazing Harvard Biovisions simulation of how a cell works; fast forward to 4:00mins for the best bit with vesicles being dragged along by ‘motor proteins’.

Moving out from the Earth, we find that the combination of salinity, pH, and temperature on which earth’s more ‘extremophile’ lifeforms thrive: thermophiles, acidophiles, psycrophiles in the lingo, are the exact same as those prevailing on Venus, Mars, and Jupiter’s moons.  Further out in the galaxy, there are candidate stars with Jupiter-sized planets at the right sort of solar distance for Earth-like temperature conditions to exist at their supposed moons (HD28185 and Gliese581 were the examples given).  So there’s hope.  Information, metabolism, blueprint  = Life.

Dartnell could see Martian material being brought back to earth for analysis at some point, but not for another ten years or so.  In the meantime, the European ExoMars probe, due for launch in 2011, will drive around the surface, drilling holes and taking samples.  It will also illuminate the landscape with ultraviolet light, organic molecules betraying themselves with their fluorescence.

No discussion on extra-terrestrial life is complete without some sort of Saganish ‘Billions’ illustration of how many stars – and presumably planets – there are in the universe: the implication being that we have a large sample size even if the odds are thin (which they aren’t necessarily).   Lewis Dartnell showed it last night.  Astronomer Stephen Warren showed it at his inaugural lecture at Imperial College tonight.  This is the now iconic Hubble deep field image showing a section of sky equivalent to only 1/30th the moon’s diameter (Warren reckoned a 1mm square at the end of your arm – sounds about right).  And most of the objects  here are galaxies.

Hubble Deep Field
Hubble Deep Field

The insufficiently humbled can check out higher resolution versions at Hubblesite.org.

“Space is big. Really big. You just won’t believe how vastly hugely mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space.”

“Life, don’t talk to me about life….”

🙂

Postscript

As a quick aside.  Before Lewis Dartnell kicked off, the organisers called for a show of hands of any first time visitors to the Royal Institution, and that turned out to be a fair chunk of audience; less than 50% I reckon, but a good number.  With my SciCom hat on, that’s really encouraging – folk taking an interest in science and technology (and they didn’t look like the UFO squad either).