Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Happy Liberation Day! Well, there is certainly some big space news this week. Of course, the biggest is the 40th anniversary of a human’s first step on another world. Did you really think it would take over 40 years for us to go back again? I figured there would be colonies on the Moon by now.
It wouldn’t be hard to do, you know. The Moon is covered with rilles, long narrow channels that look like the beds of dried-up rivers. But they weren’t made by water, they were made by lava. The lava flowed so near the surface that the tops of the lava channels collapsed.
Anyone who’s familiar with the lava tubes on the big island of Hawaii knows that the top of a lava tube doesn’t necessarily collapse. The long round tunnels go for miles under Hawaii’s volcanoes.
So, you go to the Moon and you use sonic sensing to locate a rille whose top has not collapsed. You drill an opening into the top and fashion yourself an airlock. Then you go down the tunnel an appropriate distance and build an airtight concrete wall. Then you fill the space with air. Bingo! Instant colony space!
There are other advantages to this scenario. The Moon has no air to protect it from the direct radiation of the Sun. In the daytime on the Moon, the temperatures rise to +250 degrees. That’s the reason the Apollo astronauts had to carry air conditioners around on their backs.
But we’ve never visited the Moon at night because during the Moon’s two-week long night, the temperatures fall to –250 degrees. They just didn’t want to have to deal with both extremes for long periods.
But here’s the interesting part; the temperature of any underground space anywhere is the average temperature on the ground above it. That’s the reason that spelunking on Guam (where there are lots of caves) is not perhaps the most comfortable sport.
Our temperate-zone ancestors all lived in caves for this reason. If you live in a place that routinely gets down to below zero in the winter and around 80 or 90 degrees in the summer, the average temperature in a cave is around 50 degrees. This means that the cave is wonderfully cool in the summer and life-savingly warm in the winter. No wonder we all lived in caves!
Here on Guam, the average temperature is 82 degrees and if you go crawling around in a cave where there is no wind for any length of time, you get pretty hot and damp.
Now if we return to the Moon, with its +250 degree days and –250 degree nights, it’s pretty easy to see that the temperature of any underground cavern on the Moon is going to be around zero degrees. Heating the space to a comfortable temperature for us humans wouldn’t be a problem at all! And it’s certainly easier to deal with than a 500-degree temperature range!
The walls of the cavern would be sealed to help prevent air leakage and an elaborate cleaning system could be built into the airlock to deal with the fine Moon dust that caused the Apollo astronauts so many problems.
So . . . why would we return to the Moon? Why did we go in the first place? Well, the answer to the second question is pretty easy. We were at war. They didn’t call it the space race for nothing. The Russians had declared that they were going to the Moon and we weren’t about to let them get there first.
So, we instituted a bold new space program that incidentally pumped an incredible amount of money into the economy. I remember that my uncle complained bitterly about all that money they were wasting to send a man to the Moon. And I said “But Uncle Dean, the money didn’t go to the Moon. It all stayed right here to pay the people that worked on all the projects.” And it did! The marvelous thing about a vigorous space program is that it bumps exactly the same firms and businesses and is as good for the economy as a war, but its main purpose isn’t to kill people!
So we went to the Moon the first time mainly to keep the Russians from getting there first. So, why should we go back?
Well, it looks like it’s war again, unfortunately. The Chinese have announced their intention to put a Chinese astronaut on the Moon, and once again, our government apparently isn’t going to let that pass by unchallenged.
But that’s NOT the best reason to return to the Moon. I keep hoping that someone will figure out something extremely important. The Moon is smaller than the Earth!
Hah! you say. EVERYBODY knows that! But what they may not realize are some very important physics facts. The Moon is not made of green cheese, but it is made of matter like rocks & dirt just like the Earth, so it has mass. And here’s the important physics fact: Gravity is a function of mass. The more mass you contain the more gravity you have.
Most people don’t realize that since you are made of matter and have mass, you, personally have your very own gravity field. It is very, very small, because in the cosmic scheme of things, you don’t have much mass.
The Earth is bigger than the Moon and it contains more mass. The Moon has one-sixth the Earth’s mass. So, why should we care?
Because if the Moon has one-sixth the Earth’s mass, it produces one-sixth the Earth’s gravity. How much do you weigh? No, don’t tell me, just divide your weight by six and that’s how much you would weigh on the Moon. You, big guy, with the ripped muscles, you say you weigh 180 pounds? You’d weigh 30 pounds on the Moon. You, lovely lady, you say you weigh 120 pounds? You’d weigh 20 pounds on the Moon.
And if that’s all you weigh, in a cavern full of Earth-normal air pressure, YOU could strap on a pair of wings and FLY! All by yourself with no airplanes or jet packs or anything else. YOU could flap your arms, take off and FLY!
And THAT’S why we need to go back to the Moon. Not for war, not for science, not for mining or any of the other myriad reasons the scientists like to cite. We need to go back for TOURISM, because YOU want to fly!
I’m ready! When does the rocket leave?
SOLAR ECLIPSE TOMORROW
The Moon is also making big news over a large portion of the Earth tomorrow because it’s going to pass directly between the Sun & the Earth. I enjoy living on Guam because periodically the government of Guam holds a fireworks display for my birthday. When I tell you that my birthday is tomorrow, you’ll probably realize why they’re so kind to me! (Hint: It sometimes rains on the 21st).
This year is a whole new ball game. This year it isn’t just the government of Guam that’s celebrating my birthday; it’s the whole solar system. Well, at least the Sun and the Moon. There’s going to be a solar eclipse tomorrow and you’re all invited to the party. The sun will be about 75% covered by the Moon here on Guam, and the eclipse will occur at lunchtime. Celebrate my birthday this year by safely looking at the eclipse!
Around noon on Wednesday 22 July, the people of the western Pacific will see a partial eclipse of the Sun. For over two and a half hours, the invisible Moon will glide eastward in front of the Sun, blocking out from half to all the Sun depending on your location. This is a total eclipse and because the Moon just happens to be at perigee, its closest approach to Earth for the month, it’s the longest eclipse of the 21st century. Totality will last over six minutes in some places. There won’t be a longer total solar eclipse until the year 2132.
The path of totality starts over India, travels over mainland China and exits the mainland near Shanghai. It then passes through the Ryuku Islands of southern Japan. It passes north of the Marianas Islands, through the Bonins and the Marshalls and ends northeast of American Samoa. No part of the Marianas Islands or the Federated States of Micronesia will experience tota
lity. On Guam, this is a luncheon eclipse. The Moon will contact the Sun’s edge at 11:25 a.m. and maximum coverage will occur at 12:53 p.m. At 2:15 the Moon’s shadow will leave the face of the Sun. On Guam and Saipan, about 75% of the Sun will be covered at maximum eclipse.
Because 25% of the Sun’s light will still be visible, this is a very dangerous solar eclipse. Even when it’s partially eclipsed, the Sun is still 400,000 times brighter than the full Moon. If you look at the Sun without protection, your eye lens focuses this intense radiation on the retina, the light sensitive layer of cells at the back of the eye. It is NOT safe to view this eclipse by looking at it directly at any time from anywhere in Micronesia.
Don’t use ANYTHING to look directly at the Sun. The best way to view the eclipse is to not look at it at all. Punch a tiny hole in a thin piece of cardboard or aluminum foil. Don’t look through the hole but, instead, hold it up so that the Sun’s image is projected onto a shaded viewing sheet a few inches behind it. Holes between tree leaves also act as pinhole projectors. Tiny images of the eclipsed Sun will appear on the ground in a tree’s shadow. You can also use a mirror to shine the Sun’s reflection onto a shaded wall, but DON’T shine it into anyone’s eyes.
This is the longest solar eclipse of the 21st century for two reasons. The first is that the Moon’s orbit around the Earth is not a perfect circle. This means that the Moon’s distance from the Earth varies by about 30,000 miles in each orbit. During this eclipse, the Moon is at perigee or its closest point of approach for this orbit.
The second is that the Earth’s orbit around the Sun isn’t a perfect circle either. The Earth reached aphelion, its farthest point from the Sun for the year on the fourth of July. So the Sun is close to as far away as it gets from the Earth. When the Moon is close, it looks bigger and when the Sun is far away it looks smaller. Both these factors align to make this the longest solar eclipse until 2132.
I’ll be selling solar eclipse T-shirts for $10 at the Liberation Day parade. Look for me, buy a T-shirt, and help keep the UOG Planetarium open. If you don’t find me, just e-mail me at firstname.lastname@example.org and I’ll tell you how to get a T-shirt.
I call solar eclipses, “Watching the Dragon” because many cultures all over the world said that a dragon ate the Sun in a solar eclipse. Please watch the dragon in safety tomorrow!
As I looked over the files this week, I discovered that the file that’s near and dear to my heart was bulging. So we’re off for a rocket ride through space this week. But some of our stories also involve time travel (after a fashion). So enjoy some space news with me.
There’s a small cottage industry that attempts to solve ancient mysteries by examining what was going on in the sky at the time. Astronomers have used things like visible constellations, conjunctions, phases of the moon and eclipses to date things like Julius Caesar’s first arrival in Britain, the possible time of the birth of Jesus and the exact dates of first contacts with native peoples. New research now sheds light on Homer’s arrival back in Greece after the Odyssey.
There are many debates that surround Homer’s Odyssey but one that just may be subject to scientific analysis is that there was a total solar eclipse at the time of his return to Greece.
Total eclipses are very rare. They are so rare that if what Homer describes is truly an eclipse, it could help historians date the fall of Troy, which may have occurred around the time of the events described in the Iliad and the Odyssey. But after arguing about the point for hundreds of years, historians, astronomers and classicists finally agreed that there was no corroborating evidence and tabled the discussion. Now Argentinean researchers believe they have found some overlooked passages that, taken together, may shed new light on the timing of an epic journey.
The astronomers combed through the Odyssey to find specific astronomical references that could be precisely identified as occurring on specific days throughout Odysseus’s journey. Then, they aligned each of those dates with the date of Odysseus’s return, the same day he murders the suitors who had taken advantage of his long absence to court his wife.
They identified four celestial events. The day of the slaughter is, as Homer writes more than once, also a new moon (something that’s also a prerequisite for a total eclipse). Six days before the slaughter, Venus is visible and high in the sky. Twenty-nine days before, two constellations — the Pleiades and Boötes — are simultaneously visible at sunset. And 33 days before, Homer may be suggesting that Mercury is high at dawn and near the western end of its trajectory. (Homer actually writes that Hermes — known to the Romans as Mercury — traveled far west only to deliver a message and fly all the way back east again; the researchers interpret this as a reference to the planet.)
Astronomically, these four phenomena recur at different intervals of time, so together they never recur in exactly the same pattern. The astronomers looked to see if there was any date within 100 years of the fall of Troy that would fit the pattern of the astronomical timeline. There was only one: April 16, 1178 BCE, the same day that astronomers had calculated the occurrence of a total solar eclipse.
The Argentinean astronomers acknowledge that their findings rely on a large assumption: Although the association of planets with gods was a Babylonian invention that dates back to around 2000 BCE, there’s no evidence that those ideas had reached Greece by the time Homer was writing, several hundred years later. Ultimately, whether they’re right or wrong, the researchers are interested in reopening the debate.
"Poor men, what terror is this that overwhelms you so? Night shrouds your heads, your faces, down to your knees — cries of mourning are bursting into fire — cheeks rivering tears — the walls and the handsome crossbeams dripping dank with blood! Ghosts, look, thronging the entrance, thronging the court, go trooping down to the realm of death and darkness! The sun is blotted out of the sky — look there — a lethal mist spreads all across the earth!" — Homer (translation by Robert Fagles)
And now that you’ve had your classical literature fix for the month (year?) let’s fast-forward almost 3000 years and have a look through the eyes of history.
Exactly four centuries ago, the Italian astronomer Galileo Galilei turned his ‘spyglass’ on the sky for the first time and turned the world upside down. He used his new invention to look at the moon, gaze at the Milky Way and discover the four large moons of Jupiter, which started humanity down that long road which eventually dethroned the planet Earth as the center of everything.
In synch with the International Year of Astronomy (IYA), which marks the 400th anniversary of Galileo’s discoveries, a group of astronomers and curators from the Arcetri Observatory and the Institute and Museum of the History of Science, both in Florence, Italy, are recreating the kind of telescope and conditions that led to Galileo’s world-changing observations.
Astronomers will be using the recreated ‘spyglass’ to catalogue all the objects recorded in Galileo’s ‘Sidereus Nuncius’, which is translated as the Starry Messenger. Sidereus Nuncius was published in 1610 and includes most of his early observations. Interestingly enough, since it was written not for other scientists but for the non-scientist, it’s remarkably easy to read. (Perhaps more so than Homer’s Odyssey!)
The astronomers have already observed the Moon and Saturn and are now recording images of Jupiter’s moons and the phases of Venus. Both of these observations provided Galileo with crucial evidence that most objects in the solar system orbit the Sun and not the Earth.
To recreate Galileo’s first telescope, the team first examined the lens of a telescope given to Galileo’s patron, the Grand Duke of Tuscany, Cosimo II, in 1610. They measured the shape and refractive index of the lens, and used X-ray fluorescence to determine the condition of the glass. Unfortunately, the team has not been able to build a replica of the telescope actually used by Galileo to make the observations reported in Sidereus Nuncius as only one lens of that instrument survives.
The project, however, is more ambitious than just recreating one of Galileo’s telescopes. The ultimate aim is to catch what Galileo himself might have seen. It is known that Galileo died blind and the researchers are keen to open Galileo’s tomb to retrieve DNA and diagnose his optical affliction in order to create conditions that resemble looking through Galileo’s very own eyes. Most historians think that Galileo didn’t have an eye disease however; they think that he gradually lost his eyesight because he had used his remarkable new invention to look directly at the Sun. Galileo sacrificed his corneas to tell us about sunspots.
Galileo began a whole new era of observing the sky, but life on Earth is possible because you can only observe certain things from Earth. Our atmosphere is opaque to virtually all electromagnetic radiation and trust me, this is a very good thing. About the only waves that get through our air are visible light, heat, some ultraviolet and some radio waves. We don’t have to worry about the Sun frying us with x-rays or gamma rays or microwaves because all these deadly radiations are blocked by our air. Although it keeps us alive, that lovely nitrogen/oxygen blanket does a lousy job of letting astronomers study the stars (although Galileo certainly didn’t think so!)
The only way to study these other wavelengths is to either put your detector in orbit or to boost it up beyond most of Earth’s air with a rocket or a balloon. Astronomers have recently done that and discovered something very strange.
LOUDER THAN A WHISPER
In July 2006, NASA’s Columbia Scientific Balloon Facility in Palestine, Texas
launched a balloon-borne instrument named ARCADE, which stands for the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission. ARCADE’s mission was to search the sky for heat from the first generation of stars and the balloon flew to an altitude of 120,000 feet, where the atmosphere thins into the vacuum of space. Instead they detected cosmic radio noise that booms six times louder than expected.
"The universe really threw us a curve," one of the researchers says. "Instead of the faint signal we hoped to find, here was this booming noise six times louder than anyone had predicted." Detailed analysis ruled out an origin from primordial stars or from known radio sources, including gas in the outermost halo of our own galaxy. The source of this cosmic radio background remains a mystery.
Many objects in the universe emit radio waves. In 1931, American physicist Karl Jansky first detected radio static from our own Milky Way galaxy. Similar emissions from other galaxies create a background hiss of radio noise.
The real problem is that there don’t appear to be enough radio galaxies to account for the signal ARCADE detected. To account for the noise the astronomers detected, you’d have to pack the radio galaxies into the universe like sardines. There wouldn’t be any space left between one galaxy and the next.
The sought-for signal from the earliest stars remains hidden behind the newly detected cosmic radio background. This noise complicates efforts to detect the very first stars, which are thought to have formed about 13 billion years ago — not long, in cosmic terms, after the Big Bang. Nevertheless, this cosmic static may provide important clues to the development of galaxies when the universe was less than half its present age. Unlocking its origins should provide new insight into the development of radio sources in the early universe.
"This is what makes science so exciting," says Michael Seiffert, a team member at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "You start out on a path to measure something — in this case, the heat from the very first stars — but run into something else entirely, something unexplained."
ARCADE is the first instrument to measure the radio sky with enough precision to detect this mysterious signal. To enhance the sensitivity of ARCADE’s radio receivers, they were immersed in more than 500 gallons of ultra-cold liquid helium. The instrument’s operating temperature was just 2.7 degrees above absolute zero.
A mysterious screen of extra-loud radio noise permeates the cosmos, preventing astronomers from observing heat from the first stars. The balloon-borne ARCADE instrument discovered this cosmic static (white band, top) on its July 2006 flight. The noise is six times louder than expected. Astronomers have no idea why. (Credit: NASA/ARCADE/Roen Kelly)
Don’t you just love the last sentence in the picture caption? “Astronomers have no idea why.” And that, gentle readers, is what has motivated every scientist on the face of the planet since long before Galileo. As someone once said, the real leaps in science don’t occur in huge labs with megabudgets. The real leaps in science occur when someone says “Hmmmm . . . that’s funny . . . “. Or in this case, “What was that you said? I can’t hear you!!”
Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about space and many other topics. Enjoy!