TMT versus Space Based Alternatives

With the controversy again raging over the TMT we are again seeing complete mis-representation of astronomy in the press and social media. These postings and comments make interesting reading. These show the wide range of feelings in the community. There also seems to be a misunderstanding about the roles of large telescopes in general.

TMT Rendering
An overhead view of the proposed Thirty Meter Telescope, credit TMT Observatory Corporation
The last two decades has seen an enormous advance in our understanding of the universe and its history. We now know the age of the universe, we have discovered planets around other stars, we have learned that ordinary matter makes up only a small fraction of the universe. These represent huge leaps in our understanding and these revelations have come, to the greater degree, from ground based astronomy. Many of these discoveries have been made, or greatly assisted, by the telescopes atop Mauna Kea.

Note: This post was originally written and posted to the old DarkerView blog in August 2008. Re-posted again as it answers on of the common comments in the current episode of the TMT debate. A few edits thrown in to update for the current context seven years after the first publication.

One of the themes that popped up in the comments several times was the idea that space telescopes are where to put the money and the belief that ground telescopes were “obsolete’, thus projects like TMT are not needed. This could not be further from the truth. Yes there are advantages to space telescopes with respect to interference from the atmosphere. But space telescopes face several severe and inherent disadvantages.


Space telescopes are hugely expensive for what you get. Hubble is a mere 2 meter class telescope. Very small in the terms of modern telescopes. This limits the performance drastically. Hubble can only collect a little more light than a single segment of the current Keck telescope, and Keck has 36 segments in it’s 10 meter mirror. Work out the math and you find that Keck gathers 25 times more light than than Hubble. The new James Webb Space Telescope will be a 6.5 meter telescope. The Thirty Meter Telescope will be 30 meters with 492 segments, thus will gather 28 times more light than JWST.
Continue reading “TMT versus Space Based Alternatives”

The Question

Twice in the last week I have gotten The Question. Anyone who works around the public and telescopes will get this one, and you need to be ready to answer it. There is so much history and myth around the subject that the answer can be challenging. For this one, a simple, short answer will not suffice, you need a good, concise and clear response. This is made no easier by the problem that the answer I give is not the one they want to hear.

“Have you ever seen a UFO?”

Day The Earth Stood Still
Scene from Day The Earth Stood Still (1951)
Of course by UFO they mean some sort of alien spacecraft, visitors from another star or dimension. I have seen things in the sky I didn’t know what they were, unidentified objects. But I have always been able to figure out what they were with a little checking. While the answers are usually interesting they have always been natural or human phenomena.

Note: This article originally posted Dec 13, 2008 on the old Darker View blog.

Take a breath, look the person straight in the eyes, and say it…


I have never seen any evidence of an alien visitor, nor has any of the many, many other astronomers, amateur or professional I know ever mentioned anything to me. We have all seen odd things, but no good evidence for alien visitors.

I am pretty certain there is life out there. Given the sheer odds of hundreds of billions of stars in each major galaxy and hundreds of billions of galaxies, there are simply too many chances. We now know that there are planets around just about every star, we have discovered over three hundred, and that is just around nearby stars within the reach of our instruments. There is life out there, but complex, intelligent life? That is another level of question.

They are not visiting us.

Most people who ask The Question have no concept of just how big space is, or how difficult travel among the stars would be. We have seen too many episodes of Star Trek, where the next planet is reached after the ad break and warp speed solves all of the problems. If it exists, interstellar travel will be rare and difficult, involving titanic amounts of energy. An alien ship coming into our solar system will not only been seen by every instrument we have, and there are a lot these days, but everyone with a backyard telescope. The sort of energy needed to decelerate would be more than obvious.

I have more than a little trouble with many of the eyewitness accounts, they describe a wild array of craft, all different, yet the same, as if they are just elaborating on previous stories. UFO’s with lots of lights that fly in strange ways, suddenly changing directions like the pilot has just left the bar after a heavy night. Advanced technologies will still obey the laws of physics, intelligent beings will act with purpose, what is so often described does not make any sense at all. Descriptions of little grey men are far too familiar, a head, two eyes, two arms, and two legs… far too much like us. If we ever do meet aliens they will look nothing like us, they will be truly alien.

I don’t base this answer on just circumstantial evidence, but on the lack of any reliable evidence that anything has visited. The concept of alien visitation is too extraordinary, the level of proof required is similarly extraordinary. The burden of proof lies on those that say there are aliens, and so far they have failed in that respect. I have a lot of trouble with the concept of aliens that haunt the boondocks and abduct hapless farmhands. Sorry, just not believable.

Who would I believe?

Not certain about that, but I am not sure I would trust any eyewitness. As any police detective will tell you, the human mind is simply too easy to fool, we are horrible witnesses. I would expect the best possible witness would be those who watch the sky regularly, astronomers and the far more numerous amateur astronomers, a community to which I belong.

Phil Plait at Bad Astronomy, put it very well indeed, his point is one I know well and bears repeating. The amateur astronomy community spends more time under the stars than almost any other group. We keep good optics and cameras handy, if there is anything to be seen, this large group of people would see it.

We don’t.

On any clear night, particularly weekends, there are thousands of amateur astronomers sitting with telescopes under dark skies. We see lots of things, but we know what they are. This community is educated in the many beautiful and arcane phenomena that sky can produce. We make a point to see these things and recognize them for what they are. Flickering planets low on the horizon, aircraft flares, high altitude balloons, the bright flash of a bursting meteor, satellite flares and many more. Those of us who have spent time around civilian aviation, or the military have seen even more.

If you are sure I am wrong… Show me the evidence!

Sorry, bad photos, odd Mayan carvings or unreliable eyewitness accounts don’t do it. Been there, read and seen it. When an alien ship lands on the Ellipse in front of the White House, or some other solid proof is produced I will re-examine my conclusion. But until then…


Postcard from Alaska – Trolling

The ship's electronic chart after trolling the Shark Hole in Salisbury Sound for salmon all morning
I like fishing… In moderation.

Sometimes the order of the day is fishing, fishing and more fishing. No problem, Deb loves fishing! Go have fun dear, enjoy some more fishing. I’ll just sit up here and drive.

Drive back and forth across the same spot over and over again, as slow as the boat will go. So slow the vessel barely answers the helm, taking her own sweet time to turn. It is a peaceful job of driving, as long as the little charter boats stay out of my way. I am driving a boat five times their size that just keeps moving with minimal regard to whatever I do to the wheel.

I just sit back watch the bald eagles, a humpback whale threading through the swarm of charter boats, and watch the log on the GPS display slowly fill in with the record of repeated passes…

Postcard from Alaska – Grizzly

We expected to find the bears at the back of the bay, where the stream and the salmon would be.

The mission of the morning was to see bears. So we cast off lines at Tenakee and headed up Tenakee Inlet. There are several side bays along this large inlet, each with streams that attract the bears. The salmon had not quite started to move into the streams, a bit early in the season yet, but they were around. We hoped the bears would be around as well, congregating at the streams in anticipation of their yearly feast.

It was a surprise when my dad spotted this bear, we were just starting into the bay and still a mile from where we expected to find bears. As everyone grabbed binoculars we steered towards shore to get a better look.

So often the bears will run for the woods when a large white object appears. This bear just kept eating grass. A further surprise… Just as we got closer a small bear cub appeared at mother’s side. Deep water just off the rocky shore allowed us to get the boat in quite close. On occasion the mother would look up at us as we drifted in for a closer look. The array of pointing humans, binoculars and cameras were dismissed as unimportant as she continued to graze along the shore.

The cub was a handsome fellow, dark, with a collar of golden fur. He stayed close to mother, but seemed curious. We may have been the first humans he had ever seen. He watched us intently from the safety of mother’s side.

There were several bears at the stream and the grassy flats at the top end of the bay. But the shallow water would keep us from getting anywhere near with the boat. The total was nine bears that morning, including four cubs, three with the same mother. With the morning’s plan a success, we headed back to Tenakee to collect our crab traps.

Grizzly with Cub
A mother Grizzly Bear (Ursus arctos horribilis) and cub on the shore in Long Bay, Tenakee Inlet, AK

Postcard from Alaska – A Real Bookstore

The interior of Hearthside Books on Front Street, Juneau
Leaving the women behind I stride towards the one shop I want to look through. My wife, my mother and her best friend– their idea of shopping and mine do not mesh. We know this and have arranged a plan, I leave them for an hour, to meet again at the vehicle.

I rapidly pass storefront after storefront, fine jewelry and tourist kitsch have no attraction for me. A few pretty pieces in the galleries draw a glance or two, but I turn and walk on. Memory leads me down the street and away from the docks, towards a shop I have visited in years past and I only hope it is still there.

Leaving the waterfront district and the tourist shops behind, I climb another block, to a shop occupying an oddly shaped storefront where the street splits. The result is a pie wedge shaped building, the shop I want is in the point.

This is a place I will always enjoy, a store filled floor to ceiling in books. It is a small shop, no literary supermarket, there simply isn’t the space. But the book-buyer here carefully chooses the selections, there seems to be anything you could want in the one foot of shelf space devoted to each subject.

A single rack, three feet of wall, is Sci-Fi and Fantasy. I have either read most of what is available, or know the authors displayed are not ones I enjoy. I make a couple selections, a classic Heinlein I have not read since I was a young teenager and one by Ben Bova I do not know. These I will save for traveling, to pass the time during the trip home with a long layover in Seattle.

For the next selection I rely on the advice of the sales clerk, a field guide to Alaskan birds. Every vacation is marked by what you forget at home, for this trip one of the forgotten items was a well worn copy of Sibley’s Western Birds.

Purchases made, the clerk ushers me out the door, closing time had passed while we chatted and exchanged credit card slips. I have few minutes before I must meet the gals, so I stroll back towards the docks and back into the crowds from the cruise ships.

Postcard from Alaska – Arriving Juneau

Arrival in Juneau is always pleasant. This is a very small airport, far smaller than even Kona or Hilo. As a result there are no long lines, no mile long walk to the rental car agency, no shuttle vans or snarled traffic awaiting once you do free yourself from the terminal. Walk from the gate down one flight of stairs to the single baggage claim. Forty feet from the luggage you find the rental desks, where you pick up a key and walk out into the parking lot just outside the terminal for your vehicle. As you load your luggage you can turn and see the plane sitting just the other side of the fence. A complete contrast to our experience with the enormous labyrinth that is SEA or PDX.

The jet was a 737-800 Combi model, the front half was air cargo, with a bulkhead just over the wing. We boarded and debarked by walking across the tarmac to stairs at the tail of the plane. I expect to walk across the flightline in Kona, but at SeaTac?!

Alaska Air Combi
Alaska Air flight 61 unloads cargo and passengers in Juneau