We Should Become Martians: Part I. ~ Guest Blogger Claude Plymate Returns!

  Claude Plymate is the Telescope Engineer/Chief Observer at  Big Bear Solar Observatory in California, and is the  former chief  wrangler of the McMath-Pierce Solar Telescope at Kitt Peak National Observatory Arizona for many years. He is a regular contributor to Musical Milliner.

It likely won’t come as any surprise to those of you who know me or have read some of my earlier essays that I am a strong advocate of sending humans to Mars. What might surprise you are my reasons which are more about societal needs than about scientific exploration. Our population has now passed the 7 billion mark.

There are indicators all around us that this planet cannot maintain the pressure we’re applying to its resources and resiliency. There is little reason for me to go into the details here; you are all well aware of the risks we are subjecting ourselves to. Global climate change, fresh water depletion, famine, nuclear proliferation, pandemics and war are just a sampling of the dangers we pose to ourselves. On top of our self-imposed hazards, the solar system is in general a menacing place to live.  Asteroid impacts have already wiped out the dominant species on Earth at least once before.  A nearby supernova could disrupt our ozone layer with catastrophic consequences. We are fortunate to have a strong magnetic field and atmosphere that protects us from the harsh radiation coming from solar flares but civilization has left our technology quite vulnerable to such eruptions. It doesn’t appear that a “super flare” will kill us outright but just imagine the disruption to society if the Internet, electric grid, GPS system, radio communications and even telephones suddenly and unexpectedly went ‘dark’– and not just for a few hours but possibly days, weeks or even months!

What I’m trying to point out is that there are many real threats to our civilization and even our existence as a species. Some are self-imposed, some are natural.

This leads us to the question of how to mitigate such threats to humanity.  Consider how you deal daily with risk management of other items you regard as valuable. For example, you wish to protect your documents and photos stored on your computer’s hard drive. What do you do? Of course, you backup your files onto a separate drive stored  in a separate location. (You do back up your files, don’t you?)  Applying this same rationale to society naturally leads to the conclusion that to survive long-term, humanity must expand beyond this one little planet.  Then, even if the unthinkable occurs, all that humanity has achieved won’t completely disappear from history.

The obvious first destination for a human outpost beyond Earth is Mars. Mars is the most Earthlike of the other planets within the solar system. It is close in astronomical terms and has an atmosphere. Mars is a place we can live. Plus, the lower surface gravity of Mars (about 1/4  that of Earth) makes getting on and off its surface much easier than here on the Earth.

Unfortunately, the atmosphere on Mars is very tenuous with a mean surface pressure ~ 600 Pa (0.087 psi), equivalent to an Earth atmospheric altitude of around 90,590 ft (27,612 m). On top of that, it’s a toxic mixture of mostly carbon dioxide. Anyone on the surface would have to wear a pressure suit (space suit). Even this exceedingly thin atmosphere could be used to pressurize suits & shelters. All that would be needed would be a compressor to pressurize the interiors. Simple inflatable structures could even be used for such things as storage, workshops and greenhouses. You still couldn’t breathe in the high CO2 environments but an oxygen mask would be all that’s required for people to work in otherwise shirtsleeve comfort. There are likely many plants that could thrive in these pressurized greenhouses. Obliviously, living quarters would need more oxygen to make a breathable atmosphere which is easily attainable
by liberating O2 from either CO2, water or even iron oxides (rust!) in the soil that gives the planet its red color.

Water means life. We need water to drink, water for crops and water to make oxygen. Recent Mars probes are making it clear that water (at least in the form of ice) is much more common on Mars than previously believed. What is required to harvest the water is energy; energy to drill wells or mine ice, energy to extract the O2. Possible sources for power include solar panels and/or nuclear generators and perhaps even geothermal. I suspect that the atmosphere is simply too thin to support wind power.

There are two primary arguments against going to Mars that people normally state; interplanetary spaceflight is beyond our technical ability and the cost would be far too great. I’d like to address these arguments one at a time.

Stay tuned for We Should Become Martians: Part II next week.


Life in the Universe, Part III~How to Find a Planet

Guest writer astronomer Claude Plymate, chief wrangler of the McMath-Pierce Solar Telescope at Kitt Peak National Observatory, lets us in on some fascinating facts. Geek or non, you will enjoy Claude’s latest installment

                  How to Find a Planet

Imagine gazing at an extremely bright light bulb on a dark night with a 1 mm diameter ball bearing placed about 40 feet away from it. You can probably appreciate that the blinding light would make the ball bearing all but impossible to see. Now imagine looking at the light and metal BB from a distance of about 2000 miles away. Believe it or not, the tiny angle (0.77 arcseconds) between light bulb and BB can be easily resolved in modern telescopes but the dim little BB would be completely lost in the glare of the intense light source. This is what it is like to try and spot an Earth sized planet orbiting a one of our nearby stellar neighbors. Most stars, however, are much farther away making it that much more difficult to spot any potential orbiting planets. Hunting planets around other stars is hard work! It is quite a testimonial to human ingenuity that, despite the difficulty, as of this writing over 1700 planets have been discovered orbiting stars other than our Sun! To find these extrasolar planets, or “exoplanets”, astronomers have tried various techniques with varying levels of success. Only two techniques have so far proven to be very successful.

The Radial Velocity or “Wobble” Method

It’s not quite correct to say that the Earth orbits the Sun. Technically, both the Earth and Sun orbit about the center of mass of the of the Earth-Sun system. Picture a hanging mobile sculpture, the Sun on one side and the Earth on the other with a stick between them that the whole system is suspended from. Since the Sun is much bigger and heavier than our little Earth, the mobile is suspended from a point close to but not centered on the Sun. When you spin the mobile, the planet sweeps out a large arc while the large Sun moves just a little.

The same is true for orbits. Planets swing around in their orbits, all the while gravitationally tugging on their host stars. A planet’s star reacts to this tug by circling around the balance point between them just like with the spinning mobile. Since stars are so much more massive than their planets, the radii of their orbits are correspondingly smaller. The point about which the star orbits is normally well inside the star itself!

Viewed from above – face on to the orbital plane of the stellar system – an orbiting planet will cause its star to wobble ever so slightly, like a boat rolling over waves, as it drifts through the galaxy. Astronomers spent decades carefully measuring the positions of the closest stars in our celestial neighborhood. Try as they might, no deviations in any star’s path due to a planetary system was ever detected. Either the perturbations were too small to measure or there simply weren’t any planets out there tugging on the stars.

Then, starting in the late 1980’s, astronomers tried a different approach. Instead of looking for the side-to-side wobble imposed by a face-on orbital system, they decided to use the in-and-out (radial) motion induced by an edge-on planetary system. If our vantage point happens to be more-or-less in the orbital plane of a star’s planets, the star will appear to move towards us half the time and away the other half of the time. A star’s radial (in-and-out) motion might seem like a more difficult measurement to make compared to simply plotting its zig-zag motion across the sky, but believe it or not, up until very recently (see the Photometric Method below), this is how the vast majority of extrasolar planets have been found. At the time I’m writing this, the total of number of planets found with the radial velocity method is 531!

How can astronomers measure such small radial motions in stars that are many light-years away? Spectroscopy. You are likely familiar with the fact that astronomers have long used “red shifts” of spectral features in distant galaxies to measure their “Doppler” velocity. A close look at any star’s spectrum (it’s rainbow of colors) reveals a plethora of gaps or dark lines breaking up the continuum. These “spectral lines” are due to the various gasses that make up its atmosphere. Every type of atom and molecule absorbs light at numerous precisely known wavelengths (colors). The star’s spectrum is then the combination of all the spectra of the gasses that make it up. Stars can then be categorized by their “spectral signature” – sometimes likened to a stellar barcode.

The radial velocity of a star or galaxy causes its entire spectrum to shift towards the red (longer wavelengths) if moving away from us or towards the blue (shorter wavelengths) when coming nearer. (This is how it was determined that the Universe is expanding. Hubble – the guy not the telescope – found that the farther away a galaxy is, the greater its red shift velocity tends to be. His conclusion that the Universe much be expanding was one of the major discoveries of the 20th century.) The same phenomenon is experienced with sound waves whenever a fast moving vehicle zips past making that characteristic Eeeeeeeeooooooooo sound.

We can easily distinguish that tonal shift in sound from relatively slow moving vehicles because the speed of sound itself is relatively slow (~349 m/s). The speed of light, however, is MUCH faster (~300,000,000 m/s), about 860,000 times faster! The Doppler shift seen in light is exceedingly small for slow moving objects. Still, by the 1980’s spectrographs had reached the exquisite resolution and stability required to measure the slow back-and-forth velocities of stars do-si-doing with their planets – at least their BIG planets! Small planets like the Earth are still beyond our detection limit.

Early detections were of strange so called “Hot Jupiters”, that is big planets orbiting very close to their stars. These planetary systems didn’t much resemble our solar system with its small terrestrial planets in close and the big gas giants farther out. We’d always assumed our solar system is rather typical. Is this not the case or might this simply be a “selection effect?” The bigger the planet the larger its influence on its star. Likewise, the closer the planet is to its star, the larger the perturbations of its parent star will be. So, the radial velocity method is most sensitive to big, close in planets. It’s of little surprise then that that is what we see! The farther a planet is from its star, the longer its orbital period. Finding smaller planets that are farther from their star, therefore, takes more spectral resolution and more time. To succeed in this business, you have to be both obsessively precise and patient.

Once the period of a planet’s orbit and its star’s mass (found from its spectral class) are known, determining the lower limit of the planet’s mass becomes a trivially simple calculation. The calculated mass is only a lower limit because we don’t know if we are looking truly edge-on to the stars back-and-forth motion or at some skew angle. Any deviation from straight-on will diminish the motion along our line of sight. To absolutely measure the size of a planet relative to its star takes…

The Transit or Photometric Method

Occasionally, by happy coincidence, we happen to be precisely aligned along the axis of an exoplanet’s orbital plan such that we see the planet transit across the disk of its star. This creates a mini-eclipse which ever so slightly dims the light we receive from that star. By plotting how much the star is dimmed, the relative size of the planet compared to its star can be calculated. Such measurements are known as Photometry (“photo” meaning light plus “metry” meaning to measure, is the measurement of light).

The axes of planetary orbits around stars are randomly distributed. They can be tipped at any angle from face on (looking down from above or up from below) to edge on where the orbital axis cuts right across the star. A planet the size of Earth at its distance from our Sun makes a really small target. For the Earth to appear to cut across the Sun as viewed from far outside the solar system, the viewing angle would have to be within about +/- 0.3 degrees of our orbital axis. From a random position, the chances of this are only about 1 in 300. To have a good chance of catching some planets that transit across the disk of their stars, you need to observe a LOT of stars! Also, remember that the Earth takes a year to go around the Sun.

To catch a transit of Earth from our imaginary vantage point outside of the solar system, we’d have to watch for a year to see just one transit. To be sure that what we saw was a planetary transit and not some random even (Sun spot, a random star moving across the primary target star, equipment problem, etc.), we’d need to see at least a 3 transits. And in the case of the Earth, this would take a minimum of 3 years. If you see a star dim once, you can’t say what caused it. If you see it happen twice, it’s always possible that it was caused by two separate objects. Seen a third time, you can be confident you know that it’s something in a regular orbit and you know what that orbital period is. So, not only do you need to observe a lot of stars but you need to watch them for a long time – at least several years!

Enter Kepler. Kepler is a NASA spacecraft that was launched in March of 2009. Its mission is to continuously stare at one area of the sky between the constellations Cygnus and Lyra. The spacecraft continuously monitors around 100,000 objects in a roughly 10×10 degree field of view. Being in space, Kepler does not have to contend with the shimmering fluctuations and weather variability of our atmosphere. This gives it an undisturbed and exceedingly stable vantage point resulting in unsurpassed sensitivity to stellar brightness variations. The Kepler science team recently announced more than 1200 candidate planets have been seen transiting stars in its field of view! On top of that, 54 of these planets appear to be at the right distance from their stars to be in the “habital zone” where planetary temperatures can allow liquid water to exist! Assuming these all pan out, this represents a huge jump in the number of worlds we now know about. This first list of exoplants is only the tip of the Kepler’s iceberg based on its first year of observations. We can expect many more discoveries to trickle in as Kepler continues its mission over the next few years.

Although Kepler’s transit approach to exoplanet detection is proving to be remarkably prolific, the method can’t tell us all that we’d like to know about the planets its finding. For this, other methods will need to be employed. Eventually, we should have telescopes that will be able to capture the spectrum of the planets themselves. A spectrum can tell us what makes up the planetary atmospheres. I don’t know when it’ll happen but someday we’ll hit pay dirt when oxygen and other molecules formed by biology are found in the atmosphere of an exoplanet. That will be the day when we indisputably learn that the Earth is not alone and unique in this galaxy. We will finally know that we have kindred among the stars and that life thrives throughout the Universe.

(c) GoshGusPublishing (ascap) 2011

Incrociando a Sicurezza

It was one of those late Summer days that make you forget that the season is about to turn. We happily anticipate Winter’s run up to Spring, and even more so the advent of Summer and it’s promise of long restful days. This is especially true when you are the mother of not quite grown children. Their brains rest while their bodies grow.

The end of Summer is to be ignored. We live as if there is no tomorrow, but really, all we are doing is pretending. But so what? It’s Summer!

On this particular day, this glorious temperate day, I received a phone call that it was time. I had confided my fears to my friend about walking over the Golden Gate Bridge, something locals and tourist do en masse every day. I had tried many times to walk this bridge, only to stop in abject, paralyzing fear. Irrational but tangible feelings of panic overtook me. What if someone pushed me over the rail? What if the Hand of God or some thing plucked me from the walkway and tossed me into the bay?  I couldn’t do it. My kids thought nothing of riding their bikes over the bridge. I hid my shame and made excuses.

My friend saw this obstacle as a metaphor for my collective fears. He convinced me that here lay a strong symbolic force for stepping into my new life.

I couldn’t argue his point. In fact, I decided to embrace the challenge. Not that it was easy. You see, I was not only afraid, I was stuck within all those metaphors.

Could I trust him to hold on to me? Yes. Could I trust that he would not let me come to harm? Absolutely.

So I took control by surrendering control, and put myself, literally, into the arms of the one I love.

I stalled a few yards into the journey. He whispered to me, “The trolls are not there.”  We moved forward together, and after awhile I felt  my spirit lift. I felt okay. I was more than okay. I felt free!

In freedom was pleasure. The ordinary pleasure of taking a stroll over one of the world’s most iconic bridges,  framing a view of  this gorgeous place in which we live.

I conquered this phobic fear and moved my life forward, all at once, knowing that no matter the outcome of the hardship I was facing, I would be strong enough to take all that lay ahead. I reclaimed some misplaced self-esteem, and discovered through an abiding friendship that I could love again and be loved.

I had crossed to safety.

(c)GoshGusMusic(ascap) 2011

Ascolta Tutti

Our resident guest columnist, professional astronomer  Claude Plymate of NSO at Kitt Peak takes up more Big Questions.  This week : Life in the Universe, Part I ~ Are We Martians?

One of the foremost questions in science as well as theology has always been “are we alone in the cosmos?” For the first time we are actually making real headway into answering this fundamental question. Recent results in biology have shown that life is far more tenacious than we ever could have imagined. At the same time, astronomers are demonstrating that planets are rather common companions to stars. Current estimates are that between 30 – 60% of stars include planetary systems. That would indicate that there are something like 30 to 60 billion planetary systems in our galaxy alone! That’s 5 – 10 planetary systems for each individual living on Earth. And if you assume our solar system is somewhat typical, each planetary system likely includes several planets. These overwhelmingly huge numbers makes it very easy to assume that Earth cannot be so special as to be the only place in our Universe where life has taken hold.

Observations of Mars from telescopes atop Mauna Kea, Hawaii have found evidence of methane in its thin atmosphere. This methane could be the result of geologic processes but could just as well be a side effect of life – living, farting organisms! What would if mean for the commonality of life throughout the Universe if we were to find it growing right now on our next door planet? Well, it depends. If it was found that life had spontaneously and independently sprang into existence on at least two distinct planets in our solar system, the implication would be that life is easy to get started and that life is likely to be found just about anywhere that the proper conditions exist. If however there is or ever was life on Mars, it is highly likely that it is directly related to life here on Earth and that its origin was not independent.

It is well known that throughout the history of our solar system a significant amount of asteroidal material has been flung back-and-forth between the Earth & Mars. The Martian meteorite ALH84001 made quite a media splash back in the 1996 when a team of NASA researches announced that structures imbedded in the rock appeared to show fossilized evidence of microbes. The controversy continues about the origin and meaning of these structures but it does clearly show that material from Mars occasionally does make the trek to Earth. Presumably, although not nearly as common, rocks that have been blasted off of the Earth by asteroid impacts should also occasionally find their way to Mars. (Mars’ weaker gravity and thinner atmosphere makes it easier to eject material off that planet than from the Earth. At the same time, more meteors will get pulled into Earth’s deeper gravity well.) It’s been shown that many types of microbes can easily survive inside a rock catapulted off of a planet and in the harsh conditions of interplanetary space for the time required for travel between Mars and Earth. This cross-contamination between the two planets would seem to make it highly likely that any life there is directly related to life here. The concept of life on a planet being seeded by life from elsewhere goes by the name panspermia. Panspermia makes it quite possible that we are all Martians!

As cool as it may seem to think that we might have or had microbial relatives living on Mars, it would tell us nothing about how likely or how often life gets started in the first place. Mars, however, is far from our last possible place to look for extraterrestrial life inside our solar system. Several of the moons around Jupiter and Saturn are believed to have liquid water oceans below frozen ice mantles. Any of these sub-surface oceans might make comfortable ecospheres for extraterrestrial critters. And it is rather unlikely that Earth or Martian bugs could have made the journey that far out in the solar system. Any life out there is quite unlikely to be related to us. If any other life that is truly unrelated to life here on Earth is found within our solar system, the odds are overwhelming that life must be pervasive throughout the Universe.

This leaves us at this the moment without knowing how easy it is for life to get itself started. What is clear is that once life does get going, it quickly adapts to a very wide range of conditions; I think the quote from Jurassic Park was “life finds a way.” Even if we find that life is difficult and takes a long time to get started, there are so many planets that have been around for such a very long time that the odds seem good that life – at least microbial life – is common across the galaxy.
Claude Plymate
Engineering Physicist
National Solar Observatory ry


Alla Fine: Dormire tranquillamente il mio caro amico

A dear friend has died. Unexpectedly. Inexplicably.  At an age at which one anticipates many more years yet to live.  It came as a message on my cell phone with three words:

Mark is dead.

I feel that I have lost a loved one who was in many ways my moral compass.  As the news rippled out from phones and the internet, the sadness in the air was palpable. It was numbing.  As it fell to me to bear the news to some others, the whole experience grew surreal.

This is a photograph my son took of one of Mark’s many guitars.

So many adjectives and verbs, yet I am completely at a loss to describe this man, and what he meant to me and the others whose lives he touched. Mark was my first love and became one of my most dependable and generous friends.

Many people are hurting tonight. We can’t make sense of this. I turn my face upward towards the light, and offer a prayer of  thanksgiving  for the gift of sharing part of the journey with such a kind and gentle man.

Go forth into the world in peace;  be of good courage; hold fast that which is good; render to no one evil for evil; strengthen the fainthearted; support the weak; help the afflicted; honor all people; love and serve the Lord, rejoicing in the power of the Holy Spirit. Amen.