Brief musings on a long journey

Travel can be a microcosm of life, bringing into sharper focus the absoluteness of lost opportunities, the brevity of the time between greeting and farewell, the swiftness of change both in ourselves and our situations – and the reality that today is all we have for sure. I like it: I like the things that remind me that life is for real, decisions are momentous, and we play for keeps.

AAS press release

A bit silly to wait almost two weeks to post this, but I had a great time at the American Astronomical Society meeting (January 5-9), and a press release I helped give wound up on the BBC front page on Jan 7: http://www.bbc.co.uk/news/science-environment-2564765...7

As well as lots of other places:
http://www.nbcnews.com/id/54005662
http://www.sciencedaily.com/releases/2014/01/140107170600.htm
http://phys.org/news/2014-01-stormy-stars-spitzer-probes-weather.html
http://www.astronomy.com/news/2014/01/spitzer-probes-weather-on-brown-dwarfs
http://www.popsci.com/article/technology/brown-dwarfs-racked-planet-sized-storms-molten-iron
http://www.space.com/24192-stormy-weather-brown-dwarfs-aas223.html

Pictures with new camera

The blizzard beat the guarantee, but the new camera did finally arrive.  Thanks to everyone who gave me money to buy it!  Here are a couple of pictures we took last Sunday.  For security reasons I won't post any of the adorable pictures we took of the children on this publically accessible website -- however, the children did help me choose these and optimize the display parameters.

Reeds at a frozen pond, Cathedral Pines County Park



Frozen pond near sunset, Cathedral Pines County Park

Walking home on the night of Jan 2

I start at 11:30pm.  There wasn’t much choice: I had to work late, and there’s no way our car could handle this blizzard: I couldn’t ask Jane to pick me up.  I’m well prepared: a hat and a long scarf tightly wrapped across my face, and a spare, hooded coat in case my usual denim and fleece jacket isn’t enough.

The storm is wild, and I delight in it: the dry, powdery snow whipping off the ground in swift flurries, blowing behind my glasses and stinging my face.  Is frostbite a possibility, I wonder? My shoelace breaks and unexpected hazards occur to me: what if my hands are too cold to fix it?  What if when I get home, my hands are too cold to unlock the door?

There’s about 5 inches of snow on the ground.  I find it much easier to run than to walk, because my running stride gets my feet higher, clear of the snow.  None in my shoes so far.  I cross the major road and start climbing a long hill.  I knew this would be hard, but I’m feeling frightened now by the exhausting snowdrifts and the strangeness of it all.

Stop.  I’m actually hot now from running, and being hot tends to make me anxious.  My earlier concern about frostbite is laughable now. I suddenly realize that stress level about deadlines at work is feeding an unrealistic reaction to my current situation.  Everything is going fine.  I am easily strong enough to do this.  I take off my denim fleece, button it down so no snow will get inside, and tie it by the sleeves to my backpack.  Now I am only wearing two layers.  The wind cuts icily though my sweater, but I welcome it.  Now I can run without fear of overheating.

I pass the fire station.  Its illuminated sign reads 12:16 AM, 16 degrees F.  I have seen snow drifts before, but not snow dunes: I have never seen snow that so perfectly imitates sand.  Fascinating to see this on Earth.  On the icy satellites of the outer planets, ice always acts like rock.

I pass our church: 3 miles down now, two to go.  In places the roads are well-plowed, and I run on them rather than the sidewalk, delighting in the blessed feeling of my feet not sinking in snow, but mindful of the possibility of being hit from behind by a snowplow I was too muffled to hear coming.  I look over my shoulder often.  Only one of my boots has snow inside it.  I would prefer zero.

I’m relaxed and calm now.  I thank God for this.  Everything is going to be fine.

I’m almost home, approaching Port Jefferson Harbor.  There will be no protection there from the wind.  I put my denim fleece back on, and re-wrap the scarf across my mouth.  The outside is liberally encrusted with ice from my breath.  I’m not careful enough in the cold and wind to tell if I’m getting the scarf backwards or twisted, but with every wrap I find the icy part goes outward, as it should: a small blessing but a very real one.

The wind off the harbor is every bit as cruel as I thought, but I delight in its power.  Then I see the water: the most amazing vision of the night.  No, it isn’t frozen, it’s… high.  I’ve never seen a normal tide this high.  The wind must have raised the tide in Long Island Sound.  It looks like if it were two feet higher it would be flooding the lowest part of the street.  That suggests a somewhat stronger wind could have made my walk home... very interesting indeed.  I walk along the water front, checking my initial impression that the water is ridiculously high.  Yep.

Edges of the boardwalk and wooden plank boarders of flowerbeds near the waterfront are blown clear of snow.  If I ever own any sizeable piece of land in an area where it snows like this, I will build walkways made of wooden planks two feet above the ground and only eight inches wide.  The blowing snow won’t stick to them and on a night like this they will be absolutely delightful to walk on, and worth their weight in gold if I need to do anything outside.

I wish I had the new digital camera I ordered with my Christmas money, but it will only be delivered tomorrow.  That is, it’s guaranteed to be delivered tomorrow… we’ll see who wins, the guarantee or the blizzard.  I could have taken fantastic pictures with it tonight.  On the other hand, I would have spent a lot of time taking those pictures... and getting very cold.  In fact, it’s possible that a good digital camera is the only thing that would have made my walk home tonight truly dangerous.

My little house is covered with pure white snow and still lit up for Christmas.  It looks like Heaven.  My hands are not too cold to turn the key.  As I step inside, the clock is just striking one.  I must have run faster than I thought.  Thank you, my Lord -- I’m home.

Sunday Poem

Written Sunday, November 10

The day is like the convergence of many perfections:
Golden leaves, blue sky, warm sun, cool wind.
My children's joy like a signpost, reminding me what it means:
There is a greater Father, author of gratuitous delights.

The money I wish I had could not buy these leaves, or sky, or laughter;
Not, at least, the experience of them that is this day's gift.
This Sabbath rest holds me still enough for vision.
He has taken the blinders of tomorrow's worry
From the eyes of today's delight.

Science is Fun

On Tuesday I got to talk with Scott Ransom, an astronomer who works on the science of pulsars and gravity waves – a very different subfield from mine.  He was visiting from Virginia, where he is affiliated with the National Radio Astronomy Observatory and often uses the Green Bank Telescope.  After meeting individually with me and several other astronomers in my department, Ransom gave a well-attended colloquium lecture Tuesday afternoon.  It was a typical schedule for an academic visit.  But as I thought in detail about his research, I realized all over again what an extraordinary endeavor astrophysics is – and how glad I am to be a part of it.

Pulsars, the subject of Ransom’s research, are neutron stars.  Neutron stars are the collapsed cores of exploded stars that, when they were still shining, were several times more massive than our Sun.  The violent gravitational collapse that forms a neutron star ends with typically twice the mass of the Sun crushed into a sphere just six to eight miles wide.  An average neutron star’s surface gravity is a hundred billion times stronger than Earth’s.  If one were to hit Earth (impossible since we know there are none within several light years: they would be easily visible on our X-ray sky maps), the strong rock and iron of which our lovely planet is made would be like cotton candy.  Earth would be effortlessly crushed and devoured by the neutron star’s relentless gravity, until it was reduced to a hot, ultra-dense layer roughly half an inch thick coating the surface of the neutron star.

But that’s all old hat for an astronomer.  What we especially like is spinning neutron stars: pulsars.  These emit radio beams out their north and south magnetic poles (no one is quite sure how).  If the neutron star’s rotation axis is not aligned with its magnetic axis (quite common in the Universe: even Earth’s are somewhat misaligned, which is why a magnetic compass doesn’t quite give true North), the radio beams sweep through a cone of space something like the beam from a lighthouse.  Every time one of the beams sweeps across earth, we see a flash (that is, a pulse) of radio emission.  Since nothing can speed up or slow down the rotation of a neutron star very quickly, the interval between pulses is exquisitely consistent for any given pulsar.  For a typical pulsar, this interval is a few seconds.

Consider what that means: an object twice the mass of our Sun is spinning several times a minute.

But even neutron stars like that have become comfortable, familiar objects in astronomy.  What Scott Ransom and his research group study are objects called millisecond pulsars, which rotate many times per second.  There is one – a neutron star more massive than the sun – that goes through 716 rotations every second.

These are really pretty fantastic objects.  As far as we can tell, they can only get spinning so fast by gravitationally devouring the outer layers of an orbiting companion star over a period of some millions of years.  The infalling gas from the companion star forms a rotating accretion disk that transfers angular momentum to the pulsar and makes it spin faster.  So millisecond pulsars are usually found close to (and in a binary orbit with) the dead core of a companion star whose outer layers they have eaten (this dead core is usually a kind of object called a white dwarf).  Ransom and other radio astronomers can measure the pulse times with exquisite accuracy – among the most accurate measurements in all of science – and use them to precisely calculate the orbit of the pulsar and its white dwarf companion.  In at least two cases they have seen an additional delay in the pulse times, which only happens when the pulsar is passing almost behind the white dwarf.  This delay is caused by the pulses taking longer to reach earth because they are traversing the curved space caused by the white dwarf’s gravity: a prediction of Einstein’s theory of General Relativity which has been precisely verified by observations of millisecond pulsars.

OK, millisecond pulsars are fine.  All the ones we know are in our own Milky Way Galaxy: they are too faint for us to see in other galaxies because of the huge intergalactic distances.  But Ransom had something to say about supermassive black holes in the centers of other galaxies.  Most galaxies apparently have one: our Milky Way’s is several million times the mass of the Sun.  It’s a wimp: some galaxies have a black hole tens of thousands of times bigger even than that.  So supermassive black holes are a normal part of galaxies.  Also, galaxies are colliding all the time (not to worry: the collisions take hundreds of millions of years, are usually harmless to the galaxies’ constituent stars and planets, and our Milky Way isn’t due for one until it hits the Andromeda Galaxy about 5 billion years from now).  Anyway, a frequent result of a collision between two galaxies is that they both merge into one bigger galaxy.  If both galaxies had supermassive black holes (which they usually do, as far as we can tell), the two supermassive black holes will both sink into the center of the new, merged galaxy, and eventually they will collide and merge.  In the last few centuries before they merge, they will be orbiting each other in a tight inward spiral and emitting gravitational waves (as predicted by Einstein).

Such gravitational waves haven’t yet been directly observed (they are really hard to detect), and the idea that black holes collide in merged galaxies hasn’t been proven, it’s just quite likely based on what we do know.  But Scott Ransom and his colleagues have determined that (with very careful observations) it should be possible to detect the signature of passing gravitational waves by monitoring the timing deviations they should cause in millisecond pulsars.  Basically, the gravitational waves from the colliding black holes will periodically stretch and compress the space between Earth and the millisecond pulsar, causing tiny variations in exactly when the pulses reach us.

So, astronomers get together and what do they talk about?  How to detect colliding supermassive black holes in distant galaxies by measuring the mysterious pulses of spinning neutron stars.  Even though our work is hard and our wild ideas don’t always work, I feel enormously blessed just to be able to talk and dream about stuff like that.  Yes, science is fun.

Boating, the Humphrey Bogart way

There is a boat in my driveway, on a trailer.  Both are a little unusual, which is entirely my fault: I built the boat, and modified the trailer to fit it.  The boat is inelegantly constructed of plywood and 2x4s, held together with hundreds of drywall screws and sealed with two hundred dollars’ worth of spar urethane varnish.  Its propulsion system is two oars and one thirty-four year old astronomer.  It laughs at the wakes of ferryboats and ski-boats: it is so wide and high-sided that it won’t capsize or swamp in anything less than a major storm.  On the other hand, wind and tidal currents laugh at it.  It has a top speed of about 2 mph, when I’m rowing for all I’m worth.  It also leaks about one half-gallon per hour: a rate slow enough to be irrelevant as regards safety, but fast enough to be annoying as regards shoes, lunches, and other things one might want to keep dry.

Yesterday was the boat’s fourth voyage, and likely its last before winter.  I and my friend Mark took it out with my three oldest children, ages 9, 7, and 3 (my wife and our youngest wisely stayed home).  We fought our way up the harbor into the teeth of a 10-15 mph wind, until we came to a standstill with Mark and me both rowing as hard as we could.  Plan B was working our way along the harborside, very close to shore in the lee of the forest.  But it seems the forest doesn’t have any lee with the wind coming from that direction.  It was time for Plan C.

In the 1951 movie, The African Queen, Humphrey Bogart and Catherine Hepburn accomplish a heroic navigation of a treacherous jungle river, only to find themselves entangled in a pathless, reed-choked delta.  Having exhausted all other options, Bogart climbs overboard and tries to pull their boat (the African Queen, of course) through the reeds, wading up to his neck in the leech-infested marsh.

Thankfully, though Port Jefferson Harbor does have reeds, they apparently come without leeches.  However, if you are considering getting out of a boat to wade through the shallows towing it, you should remove your cell phone from your pocket some minutes before making the attempt, rather than not finding time to do so as the boat blows swiftly toward a dangerous-looking submerged projection in the shallow water.  I jumped out and saved the boat at the cost of the cell phone: the right decision in terms of relative value, but still an idiotically preventable loss.  Then I took the bow-rope and towed the boat for several hundred yards: very satisfying to defeat the ever-moving wind and water by wading with one’s feet on solid ground.  I did find that shallows, even those full of reeds, are not always as shallow as could be wished.  But the children loved riding over the reeds.

We turned out of the main harbor and into a long, curving inlet fed by a small creek.  I waded a little more, but soon both the wind and the tidal current dropped enough that our oars were useful again.  The inlet was idyllic.  A wide diversity of boats, none ostentatious, rested at their moorings.  Lovely homes backed up against the water, which in places was lined with tall reeds – very different from the grass I had pulled us through – waving elegant-looking tassels in the wind.  The sun was warm, and hawks high overhead showed off their effortless mastery of aerodynamics. 

 

We rowed up the creek until it would no longer accommodate the boat, at which point we were within a fifty yards of a main road and a deli legendary for the quality of its sandwiches.  I considered tying up the boat and having us all troop up to the deli for a snack, but then pictured how our shoes would look plastered with the mud of the creek bank.  We turned around and rowed back, with the wind and current now blessedly in our favor.  Nine-year old Petra bailed diligently with a cracked plastic cup from a years-ago dinner at the Olive Garden.  The shadows grew long and the red sunset-light caught the trees on the east side of the harbor.  Mark delighted the children with a fairy story, complete with hilarious voices for a pet dragon and an evil witch who met her demise by being irreversibly transformed into a frog.  Comfortably before nightfall, we loaded the boat onto the trailer, bailed her out a little more, and headed home.