I've been studying brown dwarf stars for almost three years now. They are fascinating objects, more massive and hotter than planets but smaller and cooler than stars, with clouds of hot sand and molten iron vapor in their atmospheres. They glow brightest at infrared wavelengths that the human eye can't see, and we usually study them at these wavelengths. Recently, however, I've been working on a project studying them at the extreme red edge of the optical -- that is, at wavelengths near those that we can see (it turns out we can learn some unique information about their clouds at these wavelengths). This has led me to produce an image something like what a human might see, if we could look at a brown dwarf through a powerful enough telescope (or get close enough). It still isn't quite right, because it makes use of some information from light at wavelengths just a bit too long for our eyes to detect, but it's the closest that I know of to a true-color view of a brown dwarf:
The brown dwarf (called WISE 0819-0335) is the tiny red star in the center. And that's the main impression a brown dwarf would make, if you could see one with your own eyes through a powerful enough telescope: it would be faint, and deep-red. Has anyone done this? I don't know, but I think not. You'd have to put an eyepiece in one of the most powerful telescopes in the world (which normally use only electronic imaging equipment). Even then you'd only have a chance at seeing the very brightest brown dwarfs, and they'd probably be too faint for color vision -- you'd just see a faint grayish star. We'd need even bigger telescopes (or better yet, a starship) to see this kind of view for real.
What if you could get really close to the brown dwarf -- close enough that it would appear not just as a red-hued point of light but as a huge orb out the windows of your starship? It would still look deep-red, and unlike the Sun and most other stars seen up close, it would be dim enough that you could stare at it without hurting your eyes. According to some of the latest research on brown dwarfs (including my own), it would probably have dramatic cloud features. Thick, high-altitude clouds would glow only dimly, while through huge rents in them you would see down into the hotter, much brighter deep regions of the brown dwarf. Powerful winds and possibly storms full of lightning would be constantly churning and shifting the glowing clouds. It would be worth a journey of a few light years to see.
Watching for Morning
Friday, July 18, 2014
Thursday, July 10, 2014
The Late Unlamented Winter
Last winter was great and all... we had lots of good times. But still -- thank God it's over, and three cheers for summer.
In summer you have to be careful about ticks. Lyme disease is a serious concern here. But not as serious as the road to Toronto back in February!
I sweat every day on my walk to work now. But you can stand still outside and enjoy it. Not so much on the walk when the picture above was taken.
A few nights ago, 9 year-old Petra came downstairs at about 10:30pm and told me that she and her brother had decided to sue me for not putting an air conditioner in their room. They have one now, thanks to a friend from church to whom I told this story... I wasn't trying for charity, honest, I just thought it was funny... but I am grateful for the air conditioner -- and that our house no longer looks like the above picture.
A couple of weeks ago we went boating. Toward the end of the day the children were tired and I was a little warm, so I jumped off the boat to amuse them (forgetting to take my hat off). The weather was a little different from when I took this picture back in February.
OK, so maybe that should be four cheers for summer. Anyway, thank God for warmth and resurgent life and outdoor fun. Winter is good too, and I will be ready for it to come back... maybe sometime in 2016.
Wednesday, July 2, 2014
Driving in D.C.
I spent last weekend in Washington, D.C. with my wife and
our five children. We were there as part
of a larger family gathering to celebrate my father in law’s 60th
birthday. The celebration was very well
planned (none of it by me!) and involved not only a nice dinner and cake but
also visits to the National Mall and various Smithsonian museums. You may ask what museums can hold the
attention of five children with ages ranging from two months to nine
years. The answer is that the
two-month-old doesn’t count, and you can keep the rest interested for quite a long
time where there are a sufficient number of such things as rockets, space
capsules, dinosaurs, and pickled giant squids.
The important thing is to move quickly from one exhibit to the next, and
explain them each one in a brief and accessible way. It’s rather exhausting for the parents, but
it’s good mental exercise.
But all this, though more significant in the broad scheme of
things, is only context for the real topic of this post: driving in D. C. I did most of it, because I am slightly less
stressed by dangerous driving situations, and because my wife is a much better
navigator than I am. I drove so
aggressively that I was disturbed by my own conduct. I didn’t understand why I was driving like
this until my wife took over for a little while – and was forced off a highway
exit she didn’t want to take by someone who accelerated to remain in her blind
spot (I don’t think they were purposely malicious – just unobservant and
unhelpful on a crowded road). Anyway, I
realized I was driving aggressively because other ways of driving didn’t work.
Still, I am painfully aware how thin the line is between aggressive
and stupid. I am alert and observant
behind the wheel, and have excellent intuitive judgment of velocities and
tolerances. My quick, almost subconscious
decisions are rarely at fault.
Nevertheless I intensely dislike suddenly realizing that I have staked
thousands of dollars on a split-second decision whose rational basis I cannot
articulate. The fact that the decision
was good does not comfort me – how do I know the next one will be?
The reader may be wondering why I have talked about staking
money rather than the incomparably more serious risk of human lives. The answer is that I drive with tight
tolerances only when the stakes do not involve a high-momentum crash. I risk totaling my car, not my children. Nonetheless it is a car the children need,
that I cannot afford to replace, and there could be some injuries even in a
lower-velocity accident.
The most disturbing moment came when I pulled in front of a
black pickup to make a left turn into a gas station on the way home. That was
the only time I was honked at. I was making my intentions clear, but the driver
of the pickup was not slowing down to let me in. I saw that I had enough space, and I gunned
the engine and took it. It was only
afterwards that I tried to estimate how close our rear bumper had come to the
pickup’s front bumper and couldn’t do it.
Surely it was feet rather than inches… wasn’t it? Why didn’t I let the left turn go, make a
U-turn later, and come back? The answer
is that I was sure – intuitively, not rationally – that what I was doing would
work. I am not happy with answers like
that.
There are other questions, though. We needed the gas. U-turns are dangerous too. What would have happened if I had given up on
turning there?
I have to recognize the uncomfortable reality that I cannot
guarantee my family’s safety, even when I am literally at the wheel and it
seems that I am most completely in control of it. Much less can I guard effectively against
other things: falling trees, malicious strangers, cancer, and the children’s own
foolish decisions. I have the
responsibility to do what I can: to think carefully about how I drive, prune
trees, and teach good decision-making.
Still the Proverb remains true: “Unless the Lord guard a city, the
watchmen stay awake in vain.” God
promises care to his people, and I trust him.
The fact that he does not promise protection against any particular catastrophe
troubles me. But he promises his
presence and care in both peace and disaster, and that must be enough. We reached the end of the journey safely. Why?
Because I am a good driver? No.
Because he is a good God.
Saturday, June 7, 2014
How I Weathered the Tsunami
Although it was slightly edited afterwards, this post was
actually written in Chile on
April 1, the day of the large earthquake near Iquique .
Nothing about it is an April Fool’s joke, however.
I was eating dinner this evening at a nice restaurant right
on the ocean in Vina del Mar ,
Chile . My Spanish is disgracefully non-existent, so
when the waiter came up and said something to me, I thought at first that he
was telling me the restaurant would be closing soon. Then he repeated himself and I caught the
words ‘tsunami’ and ‘alerta’. Several
things came into my mind immediately: the reality of tsunamis in Chile ,
the considerable distance from where I was to any really high ground, and the
right thing to do if a tsunami were imminent: start running right away on my
best guess at an efficient route to a reachable topographic highpoint.
Anyway, having
reached this point in my thoughts about half a second after hearing the word
‘tsunami’, I jumped to my feet so quickly that the chair grated loudly on the
floor. The waiter and some of his nearby coworkers laughed at me, and told me
to relax. I remembered one other fact
about tsunamis: there can be hours of warning.
So I sat down and finished my dinner, since this was clearly
what the waiters expected and what others in the restaurant were doing. I was able to do this calmly, but I felt
impatient to get back to my hotel (just across the street) and get the full
story from a receptionist who spoke English.
I paid and tipped and crossed the street – and learned that
the warning was triggered by an earthquake near Iquique . I pictured this in my mind: Iquique is a city in far northern Chile , well
over five hundred miles from here. The tsunami will have to propagate along the
Chilean shoreline to reach us, being diffracted and weakened by the land all
the way. It is very different from the scenario I imagined earlier: a seaborne
warning system alerting us to a large undersea earthquake straight offshore
from here. So I do not expect a tsunami.
However, as I write this, I am on the eighth floor terrace
of my hotel, where I was told to go for safety. I am here only out of deference
to the authorities. Besides being skeptical about the likelihood of any sort of
tsunami tonight, I am convinced that if one did arrive that could flood my room
on the sixth floor, it would also wash away the whole hotel. But this will be a pretty good place from
which to watch (and, of course, photograph) a tsunami, in the unlikely event
that even a small one appears. And it’s a good place to write a blog post. I’m going to wait until the warning interval
expires to write the final paragraph, which will describe what the tsunami was
like or else confirm that it never arrived.
Epilogue: There was no tsunami, not even any noticeable
change in the wave pattern on the beach.
This is what I expected, once I knew where the earthquake had been. Amusingly, when I went to the same restaurant
again the next night, about five different waiters there came by and made
comforting or commiserating comments about how I had panicked the night
before. Of course, even in English I
could not hope to communicate that I had only appeared to panic. I just smiled and laughed with them at my
last night’s behavior. The things that really can throw me into heart-pounding,
hand-trembling panic are quite different: missed flights and sudden instrument
failures, for example.
I also felt something I have sometimes felt before in
situations of unexpected physical danger. It is almost the opposite of panic,
and is more like a thwarted denial. Not wanting to change my previous plans,
but recognizing that denial could be fatal, I accept the duty to preserve my
life with a sort of annoyed reluctance. If I put it into words, I might say,
“How annoying that I will now have to run for my life when I had intended to
spend the evening processing data… but it can’t be helped.”
A Perfect Night and a Surprise
March 30:
I wake up near 11. My observatory dorm room is dark, but my
body knows it is not night. I have a
thousand things to think and worry about.
Worse still, the wind is howling around the dorm. Especially since the instrument failure last
night, I really need data tonight. That
wind could stop it. If the wind is too
strong, above about forty-five miles per hour, we will not even be allowed to
open the dome.
I have slept only three hours. I desperately need more sleep, but the wind
is in my soul. My body tenses up with
every gust. I pray for sleep. I try to lie still and relax, to give my up
anxiety to God. I tell myself what is
obvious: that worry is destructive; that if anxiety about bad weather keeps me
awake, I will not be able to observe as efficiently even if I have good
weather. Worse still, I do not expect to sleep at all tomorrow: I have to
travel by car, airplane, and bus to Vina
del Mar , an unfamiliar city hundreds of miles to the
south.
I have fought this battle many times at other observatories,
and have seldom won it. I usually cannot go back to sleep once I have woken up
in the daytime. There is too much to think about, and my over-active mind does
not let me sleep. The effects of sleep
deprivation accumulate from night to night: at the end of week-long observing
runs I have sometimes been almost delirious.
Not today. Sometime
after noon, my prayers are answered, and I sleep well. I sleep through the hours when the afternoon calibrations are taken, but with this telescope that
does not matter: the daytime staff take a flawless set of calibration images
without me. I wake up in time for
dinner, and go to the door of my room.
This is the moment of truth.
There is no sound of wind now, but last time I saw the sky it was
hopelessly cloudy. The tiny, blurry
window near my toilet looks blue, but that doesn’t mean much. I pray for good weather for the thousandth
time. I take a deep breath, and I open the door.
Blue and clear. Clear
from the Andean peaks in the east down to the west horizon, where a sheet of
clouds far below us always shrouds the Pacific Ocean . Clear.
My heart is singing, full of thanks and praise.
Except that the seeing is slightly poorer, this night is
everything I hoped last night would be.
DECam performs perfectly. So does
the telescope.
Far into the night, I use the third workstation to check an
image, and I see something strange. The
now-familiar starfield is there, but several bright parallel streaks span the
entire image. This is so unusual that
even the telescope operator is surprised. “What is that?” he asked, looking
over from his own workstation.
I am wrestling with the same problem myself, but I have come
up with a guess. “I think it is an airplane,” I say. We are both staring closely at the monitor
now. The steady lights of a commercial
airliner would make the streaks we see, but airliners also have flashing
lights. If it is an airliner, why don’t
we see them? I realize suddenly that
there are three or four extremely bright stars in this image that are not in
any of the others. The new stars lie at regularly spaced intervals along the
streaks. “See,” I say to the telescope operator, “these are flashes.” We are both amused and pleased. The streaks and starbursts affect only a
small fraction of the image area: they will not hurt my science. And now we are some of the first people in
the world to have observed an airliner through a 4 meter telescope.
Dawn comes. I squeeze
the last dregs out of the night as before, and then hurry to finish backing up
my data before I need to catch my ride back to the town of La Serena .
I am exhausted, but giddy with delight.
It worked. No matter what happens in the future, I will always have
these two nights where God filled my hands with asteroids. It actually worked.
Although clouds had little effect on my observations at the
end of last night, sunrise on March 30 shows rapidly increasing sky cover that
soon fills the sky over the with torn clouds. I copy my data to a backup hard
drive and go to sleep around 8 AM.
Dreams and Nightmares
March 29: My first night actually observing with DECam has
the almost unreal quality of a dream come true. While I’ve done equally
exciting science with even bigger telescopes in the past, this project is more
fully my own than any I have attempted before with such a powerful telescope.
Tonight, given good weather and working equipment, I am going to image
asteroids fainter than any human has ever measured before. And I have good
weather and working equipment.
Good weather and working equipment. World-class telescopes such as the Blanco and
instruments like DECam are painstakingly maintained by engineers and
technicians at least as skilled as the astronomers who use them – but even so,
they are complex, one-of-a-kind systems.
A million different things can go wrong, even under a perfect sky. I have seen many bizarre failures in the
twelve years since I did my first astronomical research at a major observatory.
I cannot forget the vast number of things that all have to work together for
any night’s observations to be a success. Even though the alignment of good
weather with perfectly functioning instruments is the norm at a fine
observatory such as this one, it feels like a miracle every time. I thank God,
and I honor the human genius and the diligent work by many that makes my work
possible.
As I prepare to begin tonight’s observations, I post on
Facebook the cryptic status update I decided on weeks ago if this happened:
“Tonight is the night when I cup my hands, and God fills them full of
asteroids.”
The data are coming in, one beautiful image after
another. The sky is clear, and the
seeing is good. Pessimistic and
skeptical person than I am, I have a hard time believing this is actually
happening. I am still looking for
something I might be doing wrong, something that I have to fix in order for
this night really to be as good as it seems.
But my plans are meticulously laid, and they are unfolding
beautifully. God is pouring the
asteroid-rich data into my lap. The reality is sinking in. I am smiling a lot.
While DECam is flawlessly executing my observing scripts, I
have time to work on the huge challenge of processing this data. I started
weeks ago, downloading publically available example images from DECam and
teaching myself how to work with them.
DECam images are huge. After
processing into the format I need for asteroid searches, each image is 3.5
GB. I have two 4 TB backup hard drives,
but even this is barely enough. I am
continually running into problems doing things that are easy with smaller
images. So far I have always been able to write more computer code to solve
them. Over the next few weeks, I will be
racing against time to accurately measure the brightest asteroids in the data
before it is too late for other observers to follow them up. Without follow-up
observations, their positions will soon become uncertain. Future observers will not know where to point
their telescopes to see my asteroids, and the asteroids will join the thousands
of objects that have been seen and followed over one night or a few nights but
then lost. This is not a disaster
scientifically: my main objective is to study the statistics of extremely faint
asteroids, and I can do that perfectly well with objects that later become
lost. It is unsatisfying, however, not
to make full discoveries of at least a few asteroids when the data are this
good. I am determined to do it if I can.
But it is also necessary to enjoy the moments of
observing. I look around the control
room in leisure moments near midnight.
It is a large, well-lit room with a white linoleum floor. Three sets of
doors open out from it at somewhat odd angles, giving it the shape not of
rectangle but of a round-ish irregular polygon.
One set leads to the exit from the observatory, another set to the
refrigerator and rudimentary kitchen area, and a third to a computer room where
mere astronomers like me are not allowed – a room that is unexpectedly about to
become extremely important. The actual
observing floor is several stories above us, where the huge telescope moves
slowly in the starlight, responding with magnificent precision to our
computerized commands.
There are three major workstations in the control room, each
with six to eight widescreen monitors stacked in double rows. I am at the observer’s station. My monitors are filled with more status
information than I can possibly process mentally. Fortunately, as long as everything is going
smoothly, most of it doesn’t matter at all.
Fifteen feet to my right is the telescope operator’s station, similarly
well supplied with data displays I suspect are as complex as those in the
cockpit of a Space Shuttle. He has to
understand his displays much better than I do mine. My job is only to make this telescope do
excellent science, provided it is working.
His job is to make it work. There is also a man in the room whose
official title I forget, but who is effectively an instrument specialist. He is the one I can appeal to for immediate
rescue if something seems to be going wrong with DECam. He doesn’t have his own workstation, but will
help me with mine if something happens that I don’t understand or can’t
fix. At present, thankfully, he has
nothing to do. The telescope operator and instrument specialist are both
experts in complex systems of which I have only the most basic
understanding. I have enormous respect
for them, as for their counterparts at the other observatories I have used
throughout the world.
There is a third workstation which I have the privilege of
using if I want. It is for quick-look
processing of DECam data. Sometimes I
display an image on it, to check the starfield and admire the handful of
stunning spiral galaxies I am capturing without even meaning to. I also use it now and then to evaluate the
seeing – that is, the extent to which turbulence in the earth’s atmosphere is
blurring my images. I think the seeing is very good tonight. The images are blurred only a little more
than one arcsecond, which is about the size of a bacterium held at arm’s
length. I comment on this aloud. “We can do better,” says the instrument
specialist. He doesn’t mean that he or
anyone has control of the atmospheric turbulence, but rather that this excellent
site in the desolate foothills of the Andes
sometimes produces even better seeing than we have tonight. I hope that
tomorrow night we will indeed do even better.
At 1:30 AM DECam abruptly stops working. I and the
instrument specialist try to fix it. We restart some components of the control
software. Then we restart the whole
thing. It doesn’t work.
We call for
reinforcements. The experts work on the
system, trying things I don’t understand, ruling out possible causes of the
problem one by one. 3 AM. Outside
the southern Milky Way shines
magnificently in a perfect, moonless sky above our useless telescope. I feel
physically sick, breathless with the value of what I am losing, moment by
moment.
One does not complain in such situations. It will not help
the experts frantically working to solve the problem. Everyone knows that observing is a gamble
that can be lost, and one does not whine about losing however great the stakes.
One can pray, though.
I would like to pray aloud, as much to affirm to myself that God is in
control as to make any request of him. I am afraid of distracting those working
on the problem, however, so I kneel silently a few feet behind the observer’s
workstation.
The problem has been traced now to a serious hardware failure:
one of the computers behind the forbidden door has crashed. Restarting it could fix the problem, but
would more likely create a cascade of other issues, as the effects of the
restart propagated through the interconnected systems. A senior member of the observatory staff is
on the way. He may give us the go ahead
to restart the computer. He arrives at
about 3:45. Internally, I have already
given up the rest of the night for lost.
But it isn’t! The new system expert finds a workaround for
the ailing computer, and we are back online at 4 AM! Chile lies far west in its time
zone, so sunrise will be after eight.
There are three more usable hours in the night, and the total time lost
was only two and a half hours. Once again, I thank God, and I silently bless
the technicians who work around the clock to keep the world’s most powerful
telescopes running.
The night is no longer perfectly clear, but the clouds stay
away from my primary science field until it is getting too low to observe
anyway. The loss of 2.5 hours of perfect
weather remains painful, but the night’s data set is excellent. In the last hour before dawn, with my primary
science field setting in the west, I point the telescope instead to the positions
of two very small near-earth asteroids that recently made a close pass by Earth
and are now receding into the distance without having been observed by
anyone. If the images I am taking do
show them, I will have helped save them from being lost.
No man can hinder the dawn, and it is a fitting end even to
the most precious night. The sky brightness in my images rises abruptly, the
stars fade into the noise, and I tell the telescope operator I am finished
observing and ready to close the dome.
In my notebook I write down the parameters of the last
exposure, including the sky background value that showed me the night’s
observations were certainly over. Let there be no doubt that I used this night
down to the last dregs. Underneath the data on the last exposure, I write in my
notebook, “So ends a stomach-churning nail-biter of a night, which nevertheless
turns out to be basically successful. Thank you, my Lord!”
Brief explanation
My situation with this blog has been a bit silly. Not only have I not been finding time to write new posts, but I have not made time even to edit and publish the several long blog posts that I wrote more than a month ago about my experiences traveling in Chile -- and that trip is now more than two months ago. I am going to post all of those blog updates in quick succession now, in the hopes that they will make interesting reading even though they describe events that are now more than two months past.
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