I picked up that phrase in conversation the other day and it made me curious. I assumed that “retrograde” has its roots in the observable physical behavior of a planet or star as seen from Earth. Beyond that assumption, I did not really know what that meant. Doing a little research, it turns out that the planet Mercury will be entering retrograde on October 11th/12th (depending on your source). The word retrograde applies, in astrology, to the apparent backward motion through the zodiac of a planet. This is an observable phenomenon from Earth, and dates back to the third millennium BCE when the Sumerians made astrological observations of celestial bodies appearing to move backwards. In reality, they were moving more slowly due to the relationship in their rotational axis to that of the Earth and the other observable celestial bodies, but appeared to be moving backwards. The result of these visual relationships is retrograde motion. The 1947 “Encyclopedia of Astrology” by Nicolas DeVore describes this retrograde motion as:

“like the effect of a slow-moving train as viewed from another train traveling parallel to it but at a more rapid rate, wherein the slower train appears to be moving backwards. However, in the case of the celestial bodies it is not a matter of their actual speed of travel, but of the rate at which they change their angular relationship.”

I do not subscribe to astrology, but I do believe that most of what drives astrological definition is based on the actual physical observations of the relationship between celestial bodies in the sky. All of that to say, the physics of the stars and planets could not initially be explained by humans in scientific terms, so we were left to describe this phenomena in ways that we could understand.

It turns out that all of the planets exhibit retrograde motion as seen from Earth. The Sun and the Moon do not, but this is due to the rotational relationship of each to the Earth (the Earth revolving around the Sun and the Moon around the Earth). This motion be distinctly different from what is normally observed, it has been ascribed dramatic significance as it relates to our existence on Earth. Mercury has been of particular astrological significance when entering a retrograde period, as the mythology assigns the messenger of the gods influence over our terrestrial communications and commerce. Entering this retrograde period, Mercury has the potential to wreak havoc on our Earthly interactions with each other. Those who believe in astrology portend chaos for us during these periods.

Now, more about Mercury. As mentioned above, Mercury has been observed in the sky as long ago as the third millennium BCE. It came to represent the messenger of the gods due to the speed with which it moves across the sky. Mercury has only been visited once by spacecraft when, in 1974 and 1975, NASA’s Mariner 10 did three flybys allowing the mapping of about 40-45% of its surface. We do not know a tremendous amount about the planet closest to the sun, but here is a brief survey of what we do know:

• - It is one of four terrestrial planets in our solar system, meaning it has a rocky surface
• - Mercury has a higher iron content than any other planet in the solar system
• - There is an unstable atmosphere made from helium, hydrogen, oxygen, sodium, potassium and calcium
• - The surface has the greatest temperature difference in the solar system, due to its proximity to the Sun
• - That difference varies at its extremes by as much as 600° Kelvin
• - Mercury takes 88 days to orbit the Sun, and has the most extreme orbit of the planets
• - In its orbit, it will get as close as 46,000,000km and as far as 70,000,000km from the Sun
• - A rotation of Mercury takes about 58 days
• - Mercury is the second densest planet, after Earth, but would be first if not for gravitational compression on Earth
• - It has a large iron core that generates a magnetic field roughly 1.1% the strength of Earth’s
• - Sunlight on its surface is about 6.5 times that on Earth
• - Despite the high surface temperatures, there is believed to be ice on Mercury
• - It is believed this ice is in the deep craters and at the poles, as these are not exposed to direct sunlight.

I spent Sunday morning enjoying a great cup of coffee, The Clash, the attention of my wife and baby daughter, and thinking about why we do not have a permanent research base on the moon. As a self-appointed critic of the United States space program, I feel compelled to investigate. Given my recent post on the hard realities of a manned mission to Mars, and knowing that several nations are directing their space programs to the moon, you would think that the moon would have been on NASA’s shortlist these last thirty years. I mean… WE’VE ALREADY BEEN THERE. A few times. The reality is, the moon has not been on the list at all, at least not in a meaningful and substantive way, and our last manned visit to the moon was December 7, 1972. That was the mission of Apollo 17, the last of the six manned Apollo missions (beginning with Apollo 11 in 1969) and the end of a nearly 10 year concerted effort to put American astronauts on the moon. We put American astronauts on the moon. In 1969.

There is movement to reactivate the moon program as, back in 2004, President Bush committed us to a lunar landing no later than 2020. There is also talk at NASA regarding the creation of a permanent moon base. Money for initiating the moon program was cut out of NASA’s budget in 2006, but there is still a drive. The fact that Russia, India and China all have active moon programs, and that Japan just recently launched its first moon probe successfully is re-motivating Washington to put the moon back on the docket. China is committed to having a moon presence by 2024, less than 17 years from now. History has a way of repeating itself, and this is no more true than in the U.S. space program. The working model for the potential American moon program (when it gets re-funded), and for the creation of the base, is our very own 1960’s moon program. The thinking, I suppose, is that if it worked back then it should work for us again. The only problem is that most of the scientists and researchers that made that moon program possible are dead. There is concern that we no longer have the knowledge and expertise necessary to get to the moon successfully and that technology alone cannot make up this deficiency. There is also concern that recreating that knowledge and research will be too expensive. The question begs asking… having already been to the moon several times, and being the first to get there, how do we find ourselves again in a race to the moon? This time the technological playing field is much more flat. That, and there is more than one economic superpower in the race.

During my investigation into the moon program I took the time to actually look at Google moon. They have the equivalent for Mars. There is something amazing about being able to explore the surface of the moon and Mars from the comfort of your living room. I cannot help but feel that tools like these will inspire a whole new generation of scientists, researchers and astronauts. After a thirty year hiatus from not really doing anything beyond repetitive low Earth orbital visits via the Space Shuttle, we need a whole new generation to kick our space program into gear.

Some moon facts to jog your memories of sixth grade solar system studies:

• - The moon is an average of 238,855 miles from Earth
• - A day on the moon lasts 27.3 Earth days
• - A lunar year also lasts 27.3 Earth days
• - That is because the orbital period is equal to the rotation period
• - Surface temperatures range from -387° F to 253° F, from the dark side to the light side

NASA’s plans for the next twenty years is to play out something like this:

• - 2008/9 complete the Orion next generation spacecraft
• - 2008/9 initiate robotic spacecraft missions to explore the moon
• - 2010 the International Space Station is completed
• - 2010 the Space Shuttle is finally retired, it will have been in service nearly 30 years
• - 2014 first manned moon mission by NASA since 1972 (42 years)

Science fiction, and the planet Mars as a preferred antagonist, maps directly to our ability over the second half of the 20th century to improve our understanding of the neighboring red planet. Things really began to click in 1964. It was then that Mariner 4, sent from Earth to Mars, did a close proximity fly-by of the planet and snapped some photos. Like this one:

Really, at the time scientists were not exactly sure what they were going to see. Despite the fact that Mars had been massively researched via telescope from the comfort of Earth, scientists still harbored science fiction induced anxiety about what Mariner might reveal. Old, abandoned and decayed cities? Signs of water? Signs of great alien civilizations? What they saw is pretty much like the image above, and though without the excitement of alien civilization, nonetheless exciting for the Mariner 4 mission team. Granted, space agencies (NASA and ESA) are working overtime to establish that Mars did, in fact, once support life and to find some sort of fossil evidence of this Martian life form. The Chinese and Japanese are getting into the Mars game, with rumors that India and its fledgling space program are as well. Russia wants to get back into Mars exploration after its success in the 1970’s. This is not what I am talking about, though. We will continue to send a proliferation of unmanned probes to explore Mars, but we are at an important jumping off point in regards to our neighboring red planet. Since 1964 there have been 16 successful unmanned missions (and 23 failed missions) to Mars. NASA has a manned mission to Mars in the offing and scheduled for sometime in the range of 2015-2020… budgets permitting. We are closing in on commercial space flight with the advent of the X Prize and Richard Branson’s partnership with Burt Rutan for Virgin Galactic. There is going to be a space hotel for the families of the astronauts on the International Space Station to stay at when they are in town, just kidding… but there is talk of a space hotel. All of this activity, and while it may not have much directly to do with Mars, it is critical. This is because we are increasing our presence and access to orbit around Earth. Easy access to orbit means that the development of an orbital launch position for Mars voyages could come together relatively quickly. Orbital launch positions greatly ease the launch requirements for getting to Mars. Taking off from Earth’s surface is essentially cost prohibitive for such a mission. Launching from orbit is like sending off a cruise ship, so to speak.

So about the time most of us are getting real serious about retirement, humanity will be getting real serious about really visiting Mars. Conservatively, by the time humans are walking on the surface of Mars some sixty years will have passed since Mariner 4 did the first fly by in Mars orbit. Sixty years. We’re talking somewhere around 2025, hopefully sooner… like the 2015-2020 prescribed by President Bush. The effort to send a manned flight to Mars will have spanned my entire life. I guess it already has. Here is some interesting information about that first manned flight to Mars:

- Scientists estimate a one-way transit time to be in the range of 190-225 days

- Planning is for a surface mission of 30-90 days, putting the round-trip at 410-610 days

- For a crew of five astronauts for this duration 6,150-9150 meals will be required

- Food may be sent ahead and pre-positioned on Mars for the return trip

- What if they cannot find it?

- Assuming 1 gallon of water/astronaut per day yields needs of 2050-3050 gallons of water

- Water sources will have to be supplemented by water purification and condensation capture

- There is concern about the dust on the surface of Mars damaging the landing craft

- To enhance communications, they may boost feeds via satellites around Mars and Earth

- As many as 7 supporting unmanned flights may be necessary in advance of the manned mission

- The astronauts will most likely not have the chance to visit any of the robotic rovers already there

- Rough cost estimates put the price of the manned mission around $10-15 billion

references:

NASA Mars Exploration Program

European Space Agency (ESA)

Something about Sunday evenings and being pleasantly distracted by cosmology and astrophysics. It relaxes me.

So, the image shown above was captured by the Gemini Observatory in Hawaii. It depicts supersonic trails of plasmic hydrogen forming in the wake of enormous high speed iron objects, “bullets” if you will. These bullets are being “shot” through the humongous clouds of molecular hydrogen that comprise the Orion Nebula (around 1400 light years from Earth). Astronomers estimate that these bullets are traveling at greater than 1000x the speed of sound. That’s fast, but it is nothing compared to the fact that these bullets, a cute analogy really, are sized beyond our comprehension. The typical diameter of one of the object tips (just the tip!) is roughly 10x the size of Pluto’s orbit around the Sun. Let me say that again. The mere tips of these objects are…

TEN TIMES THE SIZE OF PLUTO’S ORBIT

Pluto is no longer a planet, by the way.

Let’s recap and feel incredibly inconsequential in the process:

Objects made of iron, larger than our solar system, are moving 250 miles per second through even larger clouds of colored gas.

More on the Gemini Observatory and this story

This evening it was appropriate to be distracted by things of stellar proportions. So much of our daily reality is ultimately abstracted from the nature around us, we should avail ourselves of every opportunity to reconnect. Do you remember how cool it was to study the sun and the solar system back in grade school? Here is a refresher:

- The sun accounts for about 99.8% of the total mass of the solar system
- It is composed of hydrogen (about 74%), helium (about 25%), and other trace elements
- The surface temperature is approximately 5,315 degrees Celsius
- The sun is about 26,000 light years from the Milky Way’s galactic center, which it orbits
- It completes one orbit of the galactic center every 225-250 million years
- The sun’s orbital speed around the galactic center is approximately 135 miles per second
- At its surface, the sun is 1000 times more vacuous than a candle flame here on Earth
- The concentrated gases beneath the surface are 100 times thinner than our air
- The highly compressed gassy matter of the interior is 10 times more dense than steel
- Magnetic hurricanes 1000’s of miles in diameter constantly erupt on the sun’s surface
- Those magnetic hurricanes are what we see and call “sun spots”

And perhaps the coolest sun fact for today is that as its surface explodes in arching plumes (see image above) it releases glowing veils of gaseous calcium. In others words, the same elemental mineral used for your bones, your teeth, and pearls jets outward from the sun in astrophysical strings that create those incredibly beautiful magnetic horse shoe curves which have been clocked at speeds up to 400 miles a second.

I cannot wait until my daughter begins to study this stuff.