Archive for the ‘Space’ Category

Wheels within Wheels

June 1, 2015

In the previous post, I left off the history of astronomy with Claudius Ptolemy, the last and greatest of the astronomers of ancient times. It was Ptolemy who brought the science of astronomy to its apex in classical times. In his treatise, the Almagest, as the Arabs came to call it, Ptolemy worked out the geocentric model with the complex system of epicycles that the ancients believed described the universe, along with a catalog of stars and constellations and tables of information on the motions of the planets and eclipses of the Sun and Moon. So well did Ptolemy do his work that the Almagest was the accepted text on astronomy for over twelve hundred years.

The science of astronomy did not stand still after the time of Ptolemy. The Western Europeans were a little distracted by the fall of the Roman Empire in the West and contributed little to the progress of learning for some centuries. Fortunately the ancient learning was preserved in the Greek East and when the Arabs conquered much of the Middle East in the century after the death of Mohammed, they were able to learn much from the peoples they ruled and soon began to make contributions of their own in science and philosophy. The Arabs translated many Greek texts into Arabic which Western scholars discovered and translated into Latin. The contributions made by the Arabs can be seen by the fact that Ptolemy’s standard text is known by its Arabic title and that many stars still retain names derived from  Arabic

Throughout the Early Middle Ages, the Muslims translated Greek texts into Arabic and so helped to preserve them until Western scholars could translate them into Latin once things had settled down in the West. The importance of the Arabic contribution can be seen by the fact that Ptolemy’s book is known by its Arabic title, not to mention that many stars are known by names derived from Arabic; Betelgeuse, Algol, Aldebaran, Deneb, Vega, and many others.

Over time, the Arabs, and later the Europeans, developed better instruments for observing the positions of the stars and planets in the sky and to predict the motions of the planets. As their techniques improved, astronomers were able to revise and update the information on planetary motions collected by Ptolemy, and they also found that more epicycles were needed to explain and predict planetary motions. The Ptolemaic model began to seem increasingly over complicated. The last major revision of the tables of planetary motions was commissioned by King Alfonso X of Castile in the thirteenth century. Alfonso, called “the Wise” was known as a patron of many branches of learning and was himself conversant in the science of astronomy. He is supposed to have remarked that if God had consulted him during the creation, he might have suggested a simpler system than the complicated bicycles of Ptolemy. The king almost certainly did not say this, but the sentiment was shared by many who began to believe the universe shouldn’t be so complicated.

Among these was a Polish priest who lived some two hundred years after Alfonso. This priest was named Mikolaj Kopernik, better known by the Latinized version of his name, Nicolaus Copernicus. Copernicus was a true renaissance man who was learned in such diverse fields as mathematics, canon law, medicine, economics, classical languages, diplomacy, politics, and astronomy. It is in that last subject that he is remembered today. Copernicus came to realize that understanding the motions of the planets would be much easier if he simply assumed that the planets revolved around the Sun rather than the Earth.

Copernicus

Copernicus

The retrograde motions of the planets could simply be explained by their overtaking the Earth as they orbit the Sun. Copernicus seems to have developed his heliocentric theory by 1514 and spent much of the rest of his life working on his book “De revolutionibus orbium coelestium” or “On the Revolutions of the Heavenly Spheres”. Although Copernicus showed the manuscript to his friends and interested scholars, he was reluctant to actually publish his masterpiece for fear of the public ridicule such a radical theory might bring him. It was only after his friends assured him that the book would be favorably received and he was dying that Copernicus agreed to publish De revolutionibus in 1543.

De revolutionibus was favorably received by the few people who actually read it. The fact was that Copernicus’s book was so abstruse and technical that only astronomers and mathematicians could really appreciate and understand it.

It was in Latin and the script was hard to read too.

It was in Latin and the script was hard to read too.

Copernicus’s heliocentric model was not generally accepted for some time. The fact that the assumption that the Sun was at the center of the Solar System made calculating the motions of the planets less complicated did not necessarily made that assumption true and there was good reason not to believe the Earth moved. In fact, the Copernican model did not make the calculations that much less complicated. Like Aristotle and Ptolemy, Copernicus believed that the planets moved in perfect circles and his theory still required some epicycles to agree with observations. It was not until 1610 when Johannes Kepler proposed his first law of planetary motion, that the planets orbit the Sun not in circles that the need for epicycles was finally done away with. The heliocentric model then clearly provided a simpler means of understanding the motions of the planets and so was quickly adopted by most astronomers even though there was not yet clear proof that it was actually true.

Which brings us back to Galileo and the Church. In 1632, the year Galileo was tried by the Inquisition, the heliocentric model was rapidly gaining acceptance, yet from a strictly scientific viewpoint, the Church was quite correct in regarding the model with skepticism, even if it was not correct from any viewpoint to put Galileo on trial, although as I said Galileo himself was mostly to blame for his troubles. And, here I have to ask again, why was the heliocentric theory adopted a century before it could be proven beyond a reasonable doubt?

Scientists like to portray themselves cool, logical, unbiased observers interested only in the facts, that is the results of their observations and experiments. Any hypothesis, no matter how attractive, must be put aside if the observations do not agree with it. In fact, scientists are subject to the same sorts of biases as everyone else and a candid view of the history of science will show many instances when scientists have clung to a hypothesis even when the facts seem to show otherwise. This is not always a bad thing. I would even go further and state that this is often a good thing. Sometimes intuition serves as a better guide to discovering the truth than logic and sometimes finding the truth requires ignoring the facts that seem to point in a certain direction while pursuing an underlying truth.

One of the biases that has proven to be most useful in understanding the nature of the universe we live in is the idea that the universe is, as bottom, a simple place that we can understand. If things get to be overly complicated, it is usually taken as a sign we are moving in the wrong direction and should seek a simpler explanation. This is no scientific reason for believing this is the case, yet this bias has proven to be useful over and over again. Ptolemy’s epicycles became more and more complicated, so astronomers switched to the simpler heliocentric system, and were proven right. Physicists and chemists in the nineteenth century were dismayed to discover more and more chemical elements with no clear pattern, until they discovered that all these elements could be explained by the three particles, electrons, neutrons, and protons found in the atoms of every element. Physicist were then confused by the many sub atomic particles they kept discovered, until they learned that these particles were composed of a handful of still smaller particles called quarks. This is really the essence of science, to find simple patterns to explain complex phenomena and this process requires intuition and imagination as much as it requires logical thinking and careful observation. So, Galileo was right, even when he was wrong.

Galileo Was Wrong

May 31, 2015

That is the idea behind an odd website that I found which promotes the theory of geocentrism or the idea that the Earth is the center of the Solar System and that the Sun revolves around the Earth. Geocentrism was, of course, the idea held by every astronomer and scientist up until 1543 when Nicolaus Copernicus proposed his heliocentric, or Sun centered, model of the Solar System. For about a century there was a fierce debate among scientists and philosophers over the true structure of the universe. Heliocentrism won out, of course, and no educated person of the twenty-first believes that the Earth is at the center of the universe. Because of this, those who historically had supported Copernicus’s model, such as Galileo are held to be on the right side of science and history, while those who clung to the older geocentrism, such as many officials of the Roman Catholic Church, seem to have been backwards and on the wrong side. This website contends that in the controversy between Galileo and the Catholic Church, the Church was, in fact, in the right and Galileo was in the wrong, hence the title. The strange thing is that the website is actually correct, in a funny sort of way. Galileo really was in the wrong and the Church was right to be skeptical of Copernicus’s theories.

The controversy between Galileo and the Church has often been depicted as part of the never ending battle between the light of science and religious ignorance. It is generally accepted by historians today that Galileo’s troubles had far less to do with an alleged anti-science position taken by the Catholic Church and more to do with contemporary Italian politics and Galileo’s own irascible personality. What is generally less well known is that the Church had good scientific reasons to oppose Galileo. Neither Copernicus or Galileo had any way to prove that the Earth moves around the Sun. With his telescope Galileo did discover the four largest moons of Jupiter and the fact that Venus shows phases, which indicates that it orbits the sun. These discoveries were certainly  suggestive in that they showed that not everything in the sky directly orbited the Earth, but it was possible that while Venus and the Galilean satellites orbited the Sun and Jupiter, the Sun and Jupiter revolved around the motionless Earth. In fact, there wouldn’t be any conclusive proof that the Earth moves until eighty years after Galileo’s death when the astronomer James Bradley discovered the phenomenon of the aberration of light caused by the Earth’s motion through space.  By this time, there was hardly any doubt about the Earth orbiting the Sun.

Why were astronomers so quick to discard the millenia-old and common sense idea that the Earth rests motionless at the center of the universe without any direct proof? The answer is that a heliocentric Solar System better accounted for the motion of the planets. In order to understand this, we will have to go back to the origins of the science of astronomy.

No one knows where or when people began to really observe the night sky and take note of the motions of the heavenly bodies. It must have seemed obvious that the Earth was a flat surface with the sky a dome enclosing it. The Sun, Moon and stars rose into the sky moved from East to West across the sky and then set beneath the Earth. At some point, these early observers noticed that not all of the objects in the sky moved along with the background of stars. These objects seemed to wander about the sky, so the Greeks referred to them as planetes, or wanderers. There were seven of these “planets”. the Sun and Moon, and five star like objects that were named Mercury, Venus, Mars, Jupiter, and Saturn. It may seem strange to refer to the Sun and Moon as planets but they like the other planets, moved across the sky against the background of the fixed stars.

The Greeks and the Romans knew that the Earth is round and the Greek philosophers such as Plato and Aristotle held that the circle was the perfect shape. Because they believed that the Heavens were perfect and unchanging, as opposed to our corrupt and changing Earth, they believed that the seven planets orbited the Earth in perfect circles. This was the model proposed by the ancient Greek astronomers, especially the last and greatest of the Hellenistic astronomers, Claudius Ptolemy, who lived in the second century AD. For this reason the geocentric model is often called the Ptolemaic model.

There was a major problem with the model proposed by the ancient Greeks, the planets do not move in perfect circles across the sky from West to East against the background of the stars. The planets moved in different paths across the sky and at different speeds. Sometimes they seemed to move backwards in what was called retrograde motion.

This image was created as part of the Philip G...

The retrograde motion of Mars(Photo credit: Wikipedia)

As Earth passes Mars, the latter planet will t...

As Earth passes Mars, the latter planet will temporarily appear to reverse its motion across the sky. (Photo credit: Wikipedia)

 

This apparent retrograde motion is is observed because the planets revolve at varying distances from the Sun and so orbit at varying velocities around the Sun. The Earth being closer to the Sun than Mars travels faster than Mars and so occasionally overtakes the other planet. Venus and Mercury travel faster than Earth and overtake us occasionally. You might be able to get an idea of how this works by considering a group of cars travelling on an Interstate. If I am driving at 60 miles per hour and pass a car that is going at 55 miles per hour, that other car will seem to be going backwards even though we are both going in the same direction. As a car travelling 65 miles per hour passes me, I will seem to be moving backwards to them.

 

In order to account for these dependencies between Aristotelian theory and astronomical observations, Greek astronomers hypothesized that while the planets move in perfect circles, they also moved in smaller circles within the circles. Thus, the heavens were full of wheels within wheels. It was Claudius Ptolemy who developed this system to the form that was used in Medieval astronomy.

epicycle-epicycle

It is easy to disparage Ptolemy for developing such a cumbersome system of concentric circles, but remember he did not have the telescope or many of the instruments invented to observe the motions of the planets that came into use in later years. He certainly cannot be blamed for assuming that the Earth is motionless. After, we cannot feel the Earth move and if we had to go by our own personal observations, we could only conclude the same. In fact, Ptolemy’s system was able to predict the motions of the planets with a high degree of accuracy and this was what the ancient and medieval astronomers were most concerned with.

There is much more to say about how later generations of Islamic and European astronomers refined and improved Ptolemy’s model as better astronomical instruments were invented and how Ptolemy came to be at last dethroned, but I am afraid that will have to wait for another post.

 

The Rolling Stones

May 5, 2015

The Rolling Stones Robert A Heinlein‘s story of the great American road trip updated for the space age. Like Heinlein’s other juvenile science fiction novels written in the 1950’s, The Rolling Stones is great fun to read and teaches the lessons in self-reliance, courage and rational thinking found in all of Heinlein’s books for young adults.

51M4VeZeDoL._SY344_BO1,204,203,200_

The plot of the Rolling Stones is simple enough. Castor and Pollux Stone, two fifteen year old twins who are Loonies, lunar colonists, want to buy a used space ship so they can begin a career in interplanetary trade. They ask their father, former mayor Roger Stone, for their inheritance in advance, but he outright refuses, insisting that they need to complete their education. The other members of the family, his wife Dr. Edith Stone, older daughter Meade, younger son Lowell, or Buster, and Roger’s mother Hazel Meade Stone, a founding mother of the Lunar Free State, convince him to buy a larger space ship for the use of the whole family. Soon, the Stones are on a trip to Mars and then the Asteroid Belt. They encounter some problems, but are able to resolve them with careful thinking and ingenuity. At the end, the Stones are on their way to Saturn to see the rings.

This book was published in 1952, before any human being had gone to space and even before Sputnik, yet Heinlein was amazingly accurate in his descriptions of how space travel would actually work. Heinlein was an engineer and he clearly put a lot of thought and research into writing this book, perhaps more thought than many might bother with for a story aimed at young adults. The Stones do not just push a few buttons and head for Mars. They must  go through a take off procedure much like that of real space craft. They must carefully calculate the proper course and account for the orbits of the planets in order to get to their destination.

With all of that being said, it is interesting to note where Heinlein and other science fiction writers of his time got things wrong. In general it has proven far more expensive and difficult to establish a human presence beyond low earth orbit than anyone anticipated. Space is a more hostile environment than thought and the extended period of weightlessness experienced by the Stones on their trip would probably leave them crippled by the time they reached Mars, unless they managed to provide some sort of artificial gravity, perhaps by rotating their ship. The depictions of the planets in Heinlein’s juveniles is far out of date. Neither Mars nor Venus is habitable without extensive terraforming and there are no natives, alas. What is most remarkable for an engineer like Heinlein is the inability to predict the electronic and computer revolutions. The computers in Heinlein’s juveniles are still huge, room sized contraptions and the characters use slide rules to perform calculations. I imagine that when the time comes when families are able to take trips to other planets, there will be an app to calculate trajectories.

I said that The Rolling Stones was the story of a road trip, but it is also the story of the ever expanding frontier. Heinlein’s political and social views were often described as libertarian, but perhaps a more accurate label would be frontier. On the frontier, whether in the Old West or in space, people cannot wait for a distant government to solve their problems or take care of their needs. By the time the government even learns of their problems, they may be dead. The people on the frontier must learn to take care of themselves and once they have become used to taking care of themselves, it is hard for them to accept the idea that their betters in a distant capital are more capable of solving problems that they are. The frontier creates a political climate that emphasizes equality over hierarchy and individual freedom over regimentation. It may be that many of the problems America is currently facing, not least an ever more intrusive and lawless government and a ever shrinking personal sphere of individual freedoms, is precisely because we no longer have a frontier. If this is the case than the sooner we get up into space, the better.

Political musings aside, The Rolling Stones is an enjoyable story that can appeal to youngsters of any age.

The Nativity According to Matthew

December 20, 2014
The Adoration of the Magi (circa 1305) by Giot...

The Adoration of the Magi

Matthew begins his Gospel with the genealogy of Jesus. I’ll skip the genealogy and go straight to his account of Jesus’s birth.

18 This is how the birth of Jesus the Messiah came about: His mother Mary was pledged to be married to Joseph, but before they came together, she was found to be pregnant through the Holy Spirit. 19 Because Joseph her husband was faithful to the law, and yet did not want to expose her to public disgrace, he had in mind to divorce her quietly.

20 But after he had considered this, an angel of the Lord appeared to him in a dream and said, “Joseph son of David, do not be afraid to take Mary home as your wife, because what is conceived in her is from the Holy Spirit. 21 She will give birth to a son, and you are to give him the name Jesus, because he will save his people from their sins.”

22 All this took place to fulfill what the Lord had said through the prophet: 23 “The virgin will conceive and give birth to a son, and they will call him Immanuel” (which means “God with us”).

24 When Joseph woke up, he did what the angel of the Lord had commanded him and took Mary home as his wife. 25 But he did not consummate their marriage until she gave birth to a son. And he gave him the name Jesus.

After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, “Where is the one who has been born king of the Jews? We saw his star when it rose and have come to worship him.”

When King Herod heard this he was disturbed, and all Jerusalem with him. When he had called together all the people’s chief priests and teachers of the law, he asked them where the Messiah was to be born. “In Bethlehem in Judea,” they replied, “for this is what the prophet has written:

“‘But you, Bethlehem, in the land of Judah,
are by no means least among the rulers of Judah;
for out of you will come a ruler
who will shepherd my people Israel.’

Then Herod called the Magi secretly and found out from them the exact time the star had appeared. He sent them to Bethlehem and said, “Go and search carefully for the child. As soon as you find him, report to me, so that I too may go and worship him.”

After they had heard the king, they went on their way, and the star they had seen when it rose went ahead of them until it stopped over the place where the child was. 10 When they saw the star, they were overjoyed. 11 On coming to the house, they saw the child with his mother Mary, and they bowed down and worshiped him. Then they opened their treasures and presented him with gifts of gold, frankincense and myrrh. 12 And having been warned in a dream not to go back to Herod, they returned to their country by another route.

13 When they had gone, an angel of the Lord appeared to Joseph in a dream. “Get up,” he said, “take the child and his mother and escape to Egypt. Stay there until I tell you, for Herod is going to search for the child to kill him.”

14 So he got up, took the child and his mother during the night and left for Egypt, 15 where he stayed until the death of Herod. And so was fulfilled what the Lord had said through the prophet: “Out of Egypt I called my son.”

16 When Herod realized that he had been outwitted by the Magi, he was furious, and he gave orders to kill all the boys in Bethlehem and its vicinity who were two years old and under, in accordance with the time he had learned from the Magi. 17 Then what was said through the prophet Jeremiah was fulfilled:

18 “A voice is heard in Ramah,
weeping and great mourning,
Rachel weeping for her children
and refusing to be comforted,
because they are no more.”

19 After Herod died, an angel of the Lord appeared in a dream to Joseph in Egypt 20 and said, “Get up, take the child and his mother and go to the land of Israel, for those who were trying to take the child’s life are dead.” (Matthew 1:18-2:20)

Most people think that the slaughter of the baby boys in Bethlehem involved the murder of hundreds or thousands of innocents. Remember, though, that Bethlehem was a small village in this time with a likely population of a few hundred. It is doubtful that more than half a dozen children were killed, not enough to make it into any other sources we have for Herod’s rule. Herod was certainly ruthless enough to order such a massacre. He had no trouble killing members of his own family if he thought they threatened his rule. In fact, Herod being an Idumean (or Edomite) and not a Jew, was a foreigner and so was as despised by many Judeans as a Roman governor would have been. If he had heard that there was a potential rival to his throne, even a child, that the Jews might rally around, he would have wasted no time in disposing of that rival.

The word Magi usually refers to Zoroastrian priests. In Greco-Roman usage the term Magi had connotations of magicians or sorcerers, exotic figures from distant lands. It is not clear just who the Magi actually were. They may indeed have been Zoroastrians. The references to the Star of Bethlehem suggest that they may have been astrologers. The Babylonians had a reputation for being skilled in astrology and magic so the Magi may have come from Mesopotamia. They may also have been Jewish since they were seeking for a king of the Jews. The fact that they were unfamiliar with the prophets may prove that they were Gentiles. The number of the Magi is not given in the Gospel. The reason that three are usually pictured  is that there were three gifts; gold, frankincense,and myrrh.

It is also not clear just what the Star of Bethlehem actually was. There have been several theories presented, but none of them are entirely satisfactory. The star might have been a supernova, perhaps in a nearby galaxy. There is no way to know for certain since any supernova remnant so far away would be difficult, perhaps impossible, to detect. It might also have been a comet. This is rather unlikely. Although a comet would behave much as the star is said to behave, hanging in the sky over a certain location for several nights, comets were universally perceived as being harbingers of disaster in ancient, and not so ancient, times. The most likely explanation is a conjunction of the planets Jupiter and Saturn. The astronomer Keppler discovered that there was indeed such a conjunction in the year 7 BC. The following year there was another conjunction of Mars, Jupiter, and Saturn. This might have been very impressive to the Magi. It may also be that the Star was a supernatural phenomenon and one that cannot be studied today. Whatever the truth of the matter is, I hope everyone has a wonderful Christmas.

The Comet and the Shirt

November 17, 2014

In earlier times people were afraid of comets. A comet in the sky was seen as a sure sign that impending disaster. It is not too difficult to understand why people would feel that way. Other heavenly bodies, such as the stars and planets move in predictable ways. The Sun rises and sets the same way every day. The Moon goes through its phases. The planets move across the background of the fixed stars. Eclipses were no doubt terrifying, but astronomers learned to predict them in ancient times. Comets, however, seemed to appear out of nowhere then disappear just as quickly. No one could tell what path they would take across the sky. Even the appearance of a comet inspired fear. The Sun and Moon looked circular and the stars and planets were points of light. A comet had a long tail streaming from it. To some the tail might look like a sword indicating divine displeasure with the inhabitants of the Earth. In any case, comets looked and acted like no other object in the heavens and that was enough to worry people.

It wasn’t until the eighteenth century that some of the mystery surrounding comets began to be dispelled. The astronomer Edmond Halley had come to believe that comets had to obey the same laws of gravitation discovered by Isaac Newton as any other object in the Solar System and beyond. He reasoned that comets orbited the Sun like the planets but they had to have extremely elongated elliptical orbits so that they would only come close enough to be observed after many years, perhaps centuries. Halley also noticed there were comet sightings approximately every 75-76 years apart and theorized that they were sightings of the same comet. He predicted that the comet, now called Halley’s Comet would return in 1758. Halley died in 1742, so he didn’t live to see his prediction come true, but his efforts showed that a comet was simply another celestial object with a motion that could be predicted, like any planet. There was nothing to fear from a comet.

Since Halley’s time, astronomers have come to learn more about comets and just this month the Philae lander from the European Space Agency’s Rosetta probe became the first man made object to land on a comet. The Rosetta probe itself was the first probe to actually orbit  a comet. This should be a proud moment for the European Space Agency and for Project Leader Matt Taylor. Instead, Dr. Taylor has found himself in the middle of a controversy and has been forced to make a tearful apology, because he wore the wrong shirt.

He helped mankind land on a comet, but Dr Matt Taylor may end up being remembered for his risqué sartorial judgement rather than his scientific acumen.

The space scientist broke down in tears today and apologised for wearing a gaudy shirt which featured cartoon images of women wearing bondage gear and firing guns.

During a press briefing this afternoon on the progress of the Rosetta mission, Dr Taylor, the lead scientist, appeared visibly upset and struggled to speak.

Eventually he said: “I made a big mistake and I offended many people and I am very sorry about this.”

Dr Taylor received a reassuring pat on the back from Andrea Accomazzo, the Rosetta flight operations director, as he went on to describe the current state of the mission.

In recent days the heavily-tattooed London scientist had become a firm favourite with the public for his unlikely appearance and enthusiastic interviews.

But the shirt has divided opinion, with many women in the science community accusing Dr Taylor of sexism.

Astrophysicist Katie Mack said earlier this week “I don’t care what scientists wear. But a shirt featuring women in lingerie isn’t appropriate for a broadcast if you care about women in science”

Here is Dr Taylor wearing the offensive shirt.

141114055922-sot-matt-taylor-philae-rosetta-scientist-shirt-00011025-story-top

Maybe the shirt is in poor taste, but so what? This man landed a probe on a comet. Surely that is more significant than his sartorial choices. After all, no one expects scientists to be fashion plates. What sort of person in their right mind is offended by this? Why do they conclude that Dr Taylor is sending some sort of misogynist message against woman in science? WHy can’t they seem to understand that this might simply be a shirt he happens to like?

With these sort of busybodies, nothing can ever be simply a personal preference with no great cultural message. No act can be a neutral one devoid of political meaning. No one can be a bystander or aspire to simply live their own life and mind their own business. You are either for social justice or against it and Gaea help you it you are perceived to be against it. These people are bullies and totalitarians, the worst sort since they are convinced in their minds that they are eternally on the side of the angels.

I think that Dr Taylor has done us all a great disservice by apologizing for offending people. He has nothing to apologize for and making apologies only enables the bullies. Instead of apologizing, we need to start telling them where they can stick their perpetual feelings of victimization.

 

Water Before Earth

September 26, 2014

I spotted this science story in the Los Angeles Times. I don’t suppose we think very much about water. Its just there. But some astronomers suspect that much of the water we drink  has been around before the Earth was formed.

Some of the water molecules in your drinking glass were created more than 4.5 billion years ago, according to new research.

That makes them older than the Earth, older than the solar system — even older than the sun itself.

In a study published Thursday in Science, researchers say the distinct chemical signature of the water on Earth and throughout the solar system could occur only if some of that water formed before the swirling disk of dust and gas gave birth to the planets, moons, comets and asteroids.

This primordial water makes up 30% to 50% of the water on Earth, the researchers estimate.

“It’s pretty amazing that a significant fraction of water on Earth predates the sun and the solar system,” said study leader Ilse Cleeves, an astronomer at the University of Michigan.

This finding suggests that water, a key ingredient of life, may be common in young planetary systems across the universe, Cleeves and her colleagues say.

I would think that water, in some form, would be rather common throughout the universe. It is made out of hydrogen and oxygen, two of the more common elements. There is more information about how the astronomers have come to their conclusions in the article.

I do not usually try to reconcile the text of the first chapters of Genesis with the findings of modern science. That is best left to those more learned in science and theology than I am. I am simply content to read Genesis to find out who created the universe and I turn to science to learn how He did it. Still, I am occasionally struck by how the writer of Genesis seems to have a better understanding of creation than any Bronze Age shepherd has any business having. Consider the very first verses.

In the beginning God created the heavens and the earth. Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.

And God said, “Let there be light,” and there was light. God saw that the light was good, and he separated the light from the darkness. God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning—the first day. 

The first thing God created was light. The earliest event in the universe we can have any knowledge of would be the Big Bang. If you have the right instruments you can still see the light of creation. But it is the second and third days that this story reminds me of.

And God said, “Let there be a vault between the waters to separate water from water.”So God made the vault and separated the water under the vault from the water above it. And it was so. God called the vault “sky.” And there was evening, and there was morning—the second day.

And God said, “Let the water under the sky be gathered to one place, and let dry ground appear.” And it was so. 10 God called the dry ground “land,” and the gathered waters he called “seas.” And God saw that it was good.

11 Then God said, “Let the land produce vegetation: seed-bearing plants and trees on the land that bear fruit with seed in it, according to their various kinds.” And it was so. 12 The land produced vegetation: plants bearing seed according to their kinds and trees bearing fruit with seed in it according to their kinds. And God saw that it was good. 13 And there was evening, and there was morning—the third day.

God created water before the dry land. Evidently water predates the planets. Now, plants are shown to be created before the Sun and Moon. This presents a problem since plants cannot survive without the Sun. But instead of plants, think the most primitive forms of life, perhaps bacteria, or even life simpler than bacteria. Some scientists believe that life may have arisen in space and traveled throughout the universe before landing on Earth. If this panspermia hypothesis is correct, then it is possible that life might also predate the formation of the solar system. There is no evidence in favor of this hypothesis. No actual life has been detected in interstellar space, though organic molecules, such as amino acids, have been.

But this is all speculation on my part and I really should leave this to wiser minds.

The Two Sides of the Moon

June 19, 2014

One of the things everyone notices when looking at the Moon are the dark spots or the Man in the Moon.

near

The Near Side of the Moon

These dark places are called “maria” from the Latin word for seas. I suppose early astronomers speculated that they really were oceans on the Moon. There is, of course no water on the Moon and the “seas” are, in fact, plains of basalt formed by volcanic eruptions when the Moon was first formed. The maria are richer in iron than the lunar highlands and so are darker.

Naturally, astronomers expected the far side of the Moon to be much like the near side. Until the space age, however, there was no way to know what the Moon’s far side was like. When the Soviet space probe Luna 3 sent back the first photographs of the far side of the Moon, in 1959, astronomers were surprised to discover that there are fewer maria on the far side.

The Far Side of the Moon

The Far Side of the Moon

Why there should be so few maria on the far side has been something of a mystery. It seems clear that the Earth must have something to do with it, but what exactly? Does the fact that the Moon has two faces have anything to do with the way it was formed? The study of exoplanets, planets orbiting other stars, may have helped to solve the mystery. Here is the article I read at Yahoo News.

Heat radiating from the young Earth could help solve the more than 50-year-old mystery of why the far side of the moon, which faces away from Earth, lacks the dark, vast expanses of volcanic rock that define the face of the Man in the Moon as seen from Earth, researchers say.

The Man in the Moon was born when cosmic impacts struck the near side of the moon, the side that faces Earth. These collisions punched holes in the moon’s crust, which later filled with vast lakes of lava that formed the dark areas known as maria or “seas.”

 

Now scientists may have solved the 55-year-old mystery; heat from the young Earth as the newborn moon was cooling caused the difference. The researchers came up with the solution during their work on exoplanets, which are worlds outside the solar system.

“There are many exoplanets that are really close to their host stars,”lead study author Arpita Roy, also of Penn State, told Space.com. “That really affects the geology of those planets.”

Similarly, the moon and Earth are generally thought to have orbited very close together after they formed. The leading idea explaining the moon’s formation suggests that it arose shortly after the nascent Earth collided with a Mars-size planet about 4.5 billion years ago, with the resulting debris coalescing into the moon. Scientists say the newborn moon and Earth were 10 to 20 times closer to each other than they are now.

“The moon and Earth loomed large in each other’s skies when they formed, ” Roy said in a statement.

I would have liked to have seen such a sight.

Since the moon was so close to Earth, the mutual pull of gravity was strong. The gravitational tidal forces the moon and Earth exerted on each other braked their rotations, resulting in the moon always showing the same face to Earth, a situation known as tidal lock.

The moon and Earth were very hot shortly after the giant impact that formed the moon. The moon, being much smaller than Earth, cooled more quickly. Since the moon and Earth were tidally locked early on, the still-hot Earth — more than 4,530 degrees Fahrenheit (2,500 degrees Celsius) — would have cooked the near side of the moon, keeping it molten. On the other hand, the far side of the moon would have cooled, albeit slowly.

The difference in temperature between the moon’s halves influenced the formation of its crust. The lunar crust possesses high concentrations of aluminum and calcium, elements that are very hard to vaporize.

“When rock vapor starts to cool, the very first elements that snow out are aluminum and calcium,” study co-author Steinn Sigurdsson of Penn State said in a statement.

Aluminum and calcium would have more easily condensed in the atmosphere on the colder far side of the moon. Eventually, these elements combined with silicates in the mantle of the moon to form minerals known as plagioclase feldspars, making the crust of the far side about twice as thick as that of the near side.

“Earthshine, the heat of Earth soon after the giant impact, was a really important factor shaping the moon,” Roy said.

When collisions from asteroids or comets blasted the moon’s surface, they could punch through the near side’s crust to generate maria. In contrast, impacts on the far side’s thicker crust failed to penetrate deeply enough to cause lava to well up, instead leaving the far side of the moon with a surface of valleys, craters and highlands, but almost no maria.

“It’s really cool that our understanding of exoplanets is affecting our understanding of the solar system,” Roy said.

I did not know that astronomers had progressed so far in the study of exoplanets that they were able to learn some details about the geology of those planets. I am glad to be living in an age in which we are learning so much about the universe we live in.

 

 

 

Brown Dwarf

April 29, 2014

Astronomers have recently discovered a previously unknown star only 7.2 light years away. You might wonder how they could miss a star that close to us. Well, Wise J085510.83-071442.5 is not a regular star. It is a brown dwarf, a star that doesn’t actually shine. Here is the story according to the Daily Mail

A brown dwarf star that appears to be the coldest of its kind – as frosty as Earth’s North Pole – has been spotted by an American astronomer.

The discovery was made using Nasa’s Wide-field Infrared Survey Explorer (Wise) and the Spitzer Space Telescope.

Images from the space telescopes also pinpointed the object’s distance at 7.2 light years away, making it the fourth closest system to our sun.

‘It is very exciting to discover a new neighbour of our solar system that is so close,’ said Kevin Luhman, an associate professor of astronomy and astrophysics at Penn State and a researcher in the Penn State Center for Exoplanets and Habitable Worlds.

‘In addition, its extreme temperature should tell us a lot about the atmospheres of planets, which often have similarly cold temperatures.’

Brown dwarfs start their lives like stars, as collapsing balls of gas, but they lack the mass to burn nuclear fuel and radiate starlight.

The newly-found brown dwarf, named Wise J085510.83-071442.5, is thought to have a chilly temperature between -48°C to -13°C (-54°F to 9°F).

Previous record holders for coldest brown dwarfs, also found by Wise and Spitzer, were about room temperature.

To understand what a brown dwarf actually is, you must realize that like people, stars are born, they live, and eventually they die. A star’s lifespan is measured in eons rather than years and they take little notice of such microscopic mayflies such as we are. A star is born when a massive cloud of gas collapses in on itself. If you recall your high school physics class, you may remember that when a gas is compressed, in this case by the protostar’s gravity, it will heat up. The energy used in compressing the gas is converted into heat. If the protostar’s mass is greater than about .08 solar masses (8% of our Sun), the center of the cloud will become dense enough and hot enough to begin fusing hydrogen into helium. A new star is born. If the mass is less than .08 solar masses than fusion will never begin and the star is stillborn. It becomes a brown dwarf.

Some of the more massive brown dwarves, around 13 to 65 Jupiter masses may fuse deuterium and lithium. They emit mostly infrared radiation. Interestingly, brown dwarves are about the same volume as Jupiter, regardless of their masses. Gravity compresses them to about the same volume. In a way, Jupiter, Saturn, and Neptune could be considered to be very low mass brown dwarves. They emit more energy than they receive from the sun. Perhaps the precise line between a massive planet and a very low mass star is not so easy to define.

General size comparison between a low mass sta...

 (Photo credit: Wikipedia)

A brown dwarf should not be confused with a red dwarf or a white dwarf. A red dwarf is a real star with a mass from about .08 to .5 solar masses. They are small and dim but they do fuse hydrogen in their core and they emit visible light. A white dwarf is a dead star. It has run out of fuel and has collapsed under its own mass until only electron degeneracy, the pressure of electrons crammed together, prevents it from collapsing any further.

But stellar corpses are another topic which I will have to write about another time.

Enhanced by Zemanta

No Muslims on Mars

February 20, 2014
Marvin the Martian

Probably not a Muslim

 

 

As humanity spreads out into space and begins to colonize other planets, it is possible that Muslims will not be among the first wave of space explorers, at least not if they obey a fatwa reportedly issued recently. I read the story in the Telegraph.

 

Muslims have been warned in a Fatwa not to go and live on Mars because it would pose “a real risk to life”, according to a Dubai news organisation.

The General Authority of Islamic Affairs and Endowment (GAIAE) in the United Arab Emirates said that anyone making such a “hazardous trip” is likely to die for “no righteous reason”.

They would therefore be liable to a “punishment similar to that of suicide in the Hereafter”, the Khaleej Times reported.

The Fatwa was apparently issued in response to the proposal from the Dutch company Mars One last year to send four people on a one-way journey to the red planet in 2022.

“Such a one-way journey poses a real risk to life, and that can never be justified in Islam,” the committee said. “There is a possibility that an individual who travels to planet Mars may not be able to remain alive there, and is more vulnerable to death.”

“Protecting life against all possible dangers and keeping it safe is an issue agreed upon by all religions and is clearly stipulated in verse 4/29 of the Holy Koran: Do not kill yourselves or one another. Indeed, Allah is to you ever Merciful,” the committee, chaired by Professor Dr Farooq Hamada, said.

Over 200,000 people have applied to be civilian-astronauts on the Mars One mission. Experts have questioned both the financial and practical viability of the mission.

The Mars One website states: “It is Mars One’s goal to establish a human settlement on Mars. Human settlement of Mars is the next giant leap for humankind.

“Exploring the solar system as a united humanity will bring us all closer together. Mars is the stepping stone of the human race on its voyage into the universe.”

 

I wonder what Dr. Farooq Hamada thinks about suicide bombers. I don’t think that risking death to explore space is the same thing as suicide. Space is a dangerous place, but we all have to die sometime and I don’t think I would mind dying while exploring strange new worlds, not that I would ever have that opportunity. I am not sure I would want to live on Mars as part of a four person colony, especially if there were no possibility of returning to Earth. When Mars One first announced their proposal to settle Mars, I thought the first colony would involve hundreds, or at least tens of colonists. I think having just three other people on a whole planet might get old after a time.

It occurs to me that Muslims might have another problem with living on another planet, besides the risk traveling there. Muslims are required to pray five times a day while facing toward the holy city of Mecca. Islamic religious authorities have already determined that a Muslim in orbit should pray facing the Earth, but what direction should a Muslim on Mars face? Perhaps they could face the Earth, but what if the Earth is on the other side of the Sun? I suppose they will work out some solution eventually, or just stay behind on Earth.

Whatever happens, I will be looking forward to seeing the colonization of Mars. It is too bad that I am not going to live long enough to see the development of terraforming techniques to make Mars and Venus livable.

 

 

 

 

Enhanced by Zemanta

The Nativity According to Matthew

December 24, 2013
The Adoration of the Magi (circa 1305) by Giot...

The Adoration of the Magi

Matthew begins his Gospel with the genealogy of Jesus. I’ll skip the genealogy and go straight to his account of Jesus’s birth.

18 This is how the birth of Jesus the Messiah came about: His mother Mary was pledged to be married to Joseph, but before they came together, she was found to be pregnant through the Holy Spirit. 19 Because Joseph her husband was faithful to the law, and yet did not want to expose her to public disgrace, he had in mind to divorce her quietly.

20 But after he had considered this, an angel of the Lord appeared to him in a dream and said, “Joseph son of David, do not be afraid to take Mary home as your wife, because what is conceived in her is from the Holy Spirit. 21 She will give birth to a son, and you are to give him the name Jesus, because he will save his people from their sins.”

22 All this took place to fulfill what the Lord had said through the prophet: 23 “The virgin will conceive and give birth to a son, and they will call him Immanuel” (which means “God with us”).

24 When Joseph woke up, he did what the angel of the Lord had commanded him and took Mary home as his wife. 25 But he did not consummate their marriage until she gave birth to a son. And he gave him the name Jesus.

After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, “Where is the one who has been born king of the Jews? We saw his star when it rose and have come to worship him.”

When King Herod heard this he was disturbed, and all Jerusalem with him. When he had called together all the people’s chief priests and teachers of the law, he asked them where the Messiah was to be born. “In Bethlehem in Judea,” they replied, “for this is what the prophet has written:

“‘But you, Bethlehem, in the land of Judah,
are by no means least among the rulers of Judah;
for out of you will come a ruler
who will shepherd my people Israel.’

Then Herod called the Magi secretly and found out from them the exact time the star had appeared. He sent them to Bethlehem and said, “Go and search carefully for the child. As soon as you find him, report to me, so that I too may go and worship him.”

After they had heard the king, they went on their way, and the star they had seen when it rose went ahead of them until it stopped over the place where the child was. 10 When they saw the star, they were overjoyed. 11 On coming to the house, they saw the child with his mother Mary, and they bowed down and worshiped him. Then they opened their treasures and presented him with gifts of gold, frankincense and myrrh. 12 And having been warned in a dream not to go back to Herod, they returned to their country by another route.

13 When they had gone, an angel of the Lord appeared to Joseph in a dream. “Get up,” he said, “take the child and his mother and escape to Egypt. Stay there until I tell you, for Herod is going to search for the child to kill him.”

14 So he got up, took the child and his mother during the night and left for Egypt, 15 where he stayed until the death of Herod. And so was fulfilled what the Lord had said through the prophet: “Out of Egypt I called my son.”

16 When Herod realized that he had been outwitted by the Magi, he was furious, and he gave orders to kill all the boys in Bethlehem and its vicinity who were two years old and under, in accordance with the time he had learned from the Magi. 17 Then what was said through the prophet Jeremiah was fulfilled:

18 “A voice is heard in Ramah,
weeping and great mourning,
Rachel weeping for her children
and refusing to be comforted,
because they are no more.”

19 After Herod died, an angel of the Lord appeared in a dream to Joseph in Egypt 20 and said, “Get up, take the child and his mother and go to the land of Israel, for those who were trying to take the child’s life are dead.” (Matthew 1:18-2:20)

Most people think that the slaughter of the baby boys in Bethlehem involved the murder of hundreds or thousands of innocents. Remember, though, that Bethlehem was a small village in this time with a likely population of a few hundred. It is doubtful that more than half a dozen children were killed, not enough to make it into any other sources we have for Herod’s rule. Herod was certainly ruthless enough to order such a massacre. He had no trouble killing members of his own family if he thought they threatened his rule. In fact, Herod being an Idumean (or Edomite) and not a Jew, was a foreigner and so was as despised by many Judeans as a Roman governor would have been. If he had heard that there was a potential rival to his throne, even a child, that the Jews might rally around, he would have wasted no time in disposing of that rival.

The word Magi usually refers to Zoroastrian priests. In Greco-Roman usage the term Magi had connotations of magicians or sorcerers, exotic figures from distant lands. It is not clear just who the Magi actually were. They may indeed have been Zoroastrians. The references to the Star of Bethlehem suggest that they may have been astrologers. The Babylonians had a reputation for being skilled in astrology and magic so the Magi may have come from Mesopotamia. They may also have been Jewish since they were seeking for a king of the Jews. The fact that they were unfamiliar with the prophets may prove that they were Gentiles. The number of the Magi is not given in the Gospel. The reason that three are usually pictured  is that there were three gifts; gold, frankincense,and myrrh.

It is also not clear just what the Star of Bethlehem actually was. There have been several theories presented, but none of them are entirely satisfactory. The star might have been a supernova, perhaps in a nearby galaxy. There is no way to know for certain since any supernova remnant so far away would be difficult, perhaps impossible, to detect. It might also have been a comet. This is rather unlikely. Although a comet would behave much as the star is said to behave, hanging in the sky over a certain location for several nights, comets were universally perceived as being harbingers of disaster in ancient, and not so ancient, times. The most likely explanation is a conjunction of the planets Jupiter and Saturn. The astronomer Keppler discovered that there was indeed such a conjunction in the year 7 BC. The following year there was another conjunction of Mars, Jupiter, and Saturn. This might have been very impressive to the Magi. It may also be that the Star was a supernatural phenomenon and one that cannot be studied today. Whatever the truth of the matter is, I hope everyone has a wonderful Christmas.


Follow

Get every new post delivered to your Inbox.

Join 488 other followers

%d bloggers like this: