Measurements Give New Insight into the Structure of the Lunar Crust

Everyone has seen the full Moon in the night sky. The familiar dark splotches called ‘maria,’ Latin for seas, create patterns on the lunar surface. Some people see a man’s face, the Man in the Moon. Others imagine a frog or a rabbit. Whatever you might picture when you look at the full Moon, the pattern of large, dark areas overlying lighter material is quite obvious. The maria are composed of lava that poured out from asteroid impacts and covered the lighter surface material.

The Lunar Nearside, credit NASA

From Earth, we only see the one side of the Moon, so you might assume this arrangement of maria over lighter material continues on the far side of the Moon. Astronomers assumed that, too, until the Russian Luna 3 spacecraft sent back the first, grainy pictures of the lunar far side in 1959. Although there were a few dark patches, they were quite a bit smaller than the familiar maria of the near side and didn’t cover much of the far side surface.

The Lunar Farside, credit NASA

Subsequent studies of the Moon revealed that the crust on the far side is as much as 10 miles (ca. 16 km) thicker than the near side crust. Because of this, asteroids can’t so easily puncture the far side crust, so fewer and smaller maria formed there. For decades, astronomers puzzled as to what might have caused this. Until recently, the best idea was that we originally had two moons. Very early on, the two collided at low speed on the far side. The material from the smaller impacting moon flowed over that side, creating the thicker crust.

Measurements made by the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012 provided more data, suggesting an impact from an outsider. "The detailed gravity data obtained by GRAIL has given new insight into the structure of the lunar crust underneath the surface," said Meng Hua Zhu, a co-author on the new paper on the subject and a scientist at Macau University of Science and Technology in China. Using computers, the researchers modeled 360 different collisions and compared all the results to what we know about the moon today. The best fit with our Moon suggests that a collision of an object 500-560 miles (ca. 805-901 km) across could have done the trick.

Artists concept of Lunar Farside collision, credit NASA

Luckily for us, there are no other such large objects wandering around near our orbit today.

On or about the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.

Writing the Perfect Picture book

When people find out I write children’s books, particularly picture books, they often tell me that they have a great idea for a picture book but have questions about the process. Can I answer a few questions, they ask.

Before they can ask me, I ask them a couple of questions. Have you read any picture book lately?

Oh, sure, they say, I read my kids all the Dr. Seuss books when they were little. And I took my grandkids to see the movie 'Where the Wild Things Are.'

But, I ask, have you read any picture books published recently? They often have not.

Then I ask if they have actually written the book. Again, I often hear “No, it’s an idea I have.”

The Writing.

People think writing a picture book is easy. It’s only 500 – 1000 words. No problem. But the very brevity of picture books is what makes them so difficult to do well.

Let’s say you write an 80,000-word adult novel. If 5% of the writing is weak, which doesn’t seem so horrible (a 95% success, that’s a grade of A), that means you have 4,000 poorly-chosen words (or badly constructed sentences) an average of one or two per page of 200 words.

If 5% of your writing on an 800-word picture book is weak, you’ll have 40 bad words, more than one on a page with only 30 words or less on it. While it’s the same percentage, they will stand out more far more obviously.

I tell them to go to the library or a book store and read dozens of picture books. See what works; learn why they were good enough to get published.

Most publishers want their picture books to cover 24 pages. While they generally do not want you to indicate the page breaks, you have to think in terms of 24 pages (or 28 or 32, whatever the publisher’s guidelines state). Publishers will state on their web pages word count and preferred page length, so make darn sure you adhere to those guidelines.

Check Age-Appropriateness.

Let an elementary teacher read your picture book. Take her criticism seriously. Read it to a child of the appropriate age. Take his comments seriously, but remember that a young child won’t use the words an adult would. You need to learn to understand child-speak and note their facial expressions and body language as you read it. Having trouble doing that? Then why are you writing books for young children?

Write and rewrite it. My first picture book, only 800 words, took me five years to get what I felt were the exact right words for it.

Make sure it is appropriate for the age you intend it for. While it may sound perfectly clear and understandable to you, you are not a six-year-old child. One of my most used reference books, when I write for kids, is “Children’s Writer’s Word Book” by Alijandra Mogilner. It lists common words understandable by grade level. Think of this book as a thesaurus for child-compatible words. It gives alternative words to use for other grade levels. Suppose you use the word novel, as in new or unusual. ‘Novel’ is a 5^th-grade word used in that context, so if you put it in a book meant for 1^st graders, they won’t know what it means. The book suggests ‘new’ for kindergarteners, ‘latest’ for 1^st grade, ‘fresh’ or ‘modern’ for 2^nd graders, and so on. Each of those can be looked up to possibly give you more options.

Will Your Audience Understand It?

When you are done with your first draft, and indeed after every draft, run the story through a readability checker. Several can be found online, like http://datayze.com/readability-analyzer.php.  Or, here, you can find 10 different readability calculators: https://www.wyliecomm.com/2018/11/10-free-readability-calculators/. Try them all on the same piece of writing, see which ones help you the most.

Illustrating It.

Perhaps the most-asked question I get from would-be picture book authors is where do I fond my illustrators. I do not find illustrators. My books are published by a full-service indie press, and they have in-house illustrators. And, in general, you do not want to provide illustrations with your book. That just gives publishers two possible reasons to reject your book. If you or your friend who draws as a hobby have no experience illustrating picture books, you are not likely to provide illustrations the publisher wants.

As you write your books, you do have to think in pictures, even if your pictures are nothing like what the illustrator eventually comes up with. Make sure the story has action in it, action that can be illustrated. If you write a story where the same picture works for several pages, the publisher won’t want it and the illustrator won’t want to illustrate it. Picture books are really two books in one, the words and the pictures. And if you’re a 6-year-old kid, which will be more important to you? Make sure your picture book allows for interesting, varied, and exciting pictures.

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Bio.

I currently have 5 published books for children, with three more currently in the illustration stage with my publisher, 4RV Publishing. I spent 40 years as the director of a planetarium where I brought the wonders of the universe to audience members from 4 to 104. I have raised four children, my best audience and greatest critics.

Should We Announce Our Presence?

Let’s say you and a group of friends invent a transporter device, like on Star Trek, but with one major difference: You have no control over where it would send you. Suppose, on your first trip, you and your friends found yourselves in a back alley of a totally unknown neighborhood in a foreign country. Would you announce your presence? Back in your own country, the news regularly reports stories of strangers being treated very badly by locals. Sure, those are isolated events. Most people back home act quite friendly to others. But you don’t know much about the customs and mores of these people. What do you do?

Image your machine transported you to some alien planet, populated with local beings, where you would be the alien visitors. You know nothing about these beings. Are they so much more superior to you that they might look on you as you see a mosquito? Might they just eat you to sample a new delicacy?

That’s a quandary that faces humanity on a larger scale. We have discovered thousands of alien planets, many of which seem quite capable of supporting life, with more discoveries of potentially life-bearing planets coming every year. For some time, Project SETI (Search for Extraterrestrial Intelligence) has been actively searching for signals from aliens that populate other planets. That’s like you and your friends in the back ally of an unknown foreign country simply listening to a radio broadcast to see what you can learn about the local people.

But now, a newly formed group known as METI (Messaging Extra Terrestrial Intelligence), led by the former SETI scientist Douglas Vakoch, wants to take that a step farther and broadcast our existence to the universe. Some scientists argue vehemently against such an idea. Remember, they warn, what happened to the native populations of the Americas after the discovery of the New World by Europeans. In some areas, 90% or more of the natives were killed and their cultures virtually wiped out.

That, claim some voices of caution, is most likely our fate if other, alien races discovery our existence.

In 1974, the director of Arecibo Radio Telescope in Puerto Rico, then the largest telescope in the world, wanted to showcase its newly renovated abilities. In a demonstration meant more for publicity than science, they designed and sent a 167-second radio message to a cluster of 300,000 stars, known as M-13. M-13 is 25,000 light years from earth, meaning we can’t get a return signal for 50,000 years.

Martin Ryle, then the Royal Astronomer of England fired off a strong condemnation of the stunt. He argued that ‘‘any creatures out there [might be] malevolent or hungry.’’ Ryle further demanded that the International Astronomical Union, the international governing body of things astronomical, forbid any further communication attempts to alien planets.

Today, the voices of dissent echoing Ryle’s caution include scientific luminaries like Elon Musk and Stephen Hawking. Like Ryle, they warn that aliens might treat us the way Cortez treated the Aztecs five centuries ago. The problem, they explain, is that humans have existed for a mere few hundred thousand years on a planet only 4.5 billion years old. The Milky Way has been making planets for more than 10 billion years. Any race of beings who detect our messages likely will be as advanced compared to us as we are to bacteria, and view Earth as a place with riches to be exploited. That doesn’t bode well, they say, for our continued existence.

Of course, not all humans are so brutal and calloused. Many actively work to help others less fortunate and less well-educated than they are. We’ve protected many species and environments on our planet. But as recent political events show, that may not be a permanent situation. And as the fate of those original natives of the Americas reminds us, such kindness towards others often takes a back seat when the opportunity to enrich ourselves arrives.

So, what do you think? Should we announce our existence and location to the universe at large? Or should we remain in our dark alley corner of the universe, eschewing contact with others? Please comment with your thoughts.

Water on Mars from Deep Groundwater Sources

In 2015, NASA announced the discovery of water flowing down the sides of craters on Mars. NASA calls them Reoccurring Slope Lineae, RSL for short. This seemed to answer the question of whether liquid water currently existed on Mars. And since liquid water is believed to be a prime requirement for life, the discovery also reinvigorated the discussion of life, even if only microscopic, on the red planet. You can see a NASA video montage of some RSLs at https://youtu.be/H44-XrGH5IQ.

Reoccurring Slope Lineae on Mars, credit NASA

In 2017, some researchers published papers suggesting RSLs were not from water but consisted of sand sliding down the slopes, driven by carbon dioxide that sublimated from dry ice just below the surface. Carbon dioxide, being a relatively heavy gas, flows downhill and carries sand grains with it. The researchers suggested that the sand just below the surface might be darker, having not been bleached by UV radiation from the sun.

The consensus of scientific opinion, however, rested with water flow, but many wondered if water just below the surface of the cold planet could never melt. Recently, Essam Heggy, a research scientist at the University of Southern California and NASA's Jet Propulsion Laboratory, and Abotalib Z. Abotalib, a postdoctoral research associate at USC, suggested that the flows are triggered not by near-surface water but rather from deep below the surface. "We propose an alternative hypothesis, that they originate from a deep, pressurized groundwater source, which comes to the surface, moving upward along ground cracks," said Hegggy.

They compared Martian geological features to similar ones on Earth and determined that heat flow in the Martian subsurface was similar to that in desert regions here on Earth. This research, the two concluded, indicates that RSL water is probably coming from deeply buried, briny aquifers.

This even explains the seasonal aspect of the flows. "The system shuts down during winter seasons, when the ascending near-surface water freezes within fault pathways, and resumes during summer seasons when brine temperatures rise above the freezing point," the researchers wrote.

The new study says nothing about the existence of life on Mars, but it will surely strengthen arguments for at least microbial Martians living below the surface.

       On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

      This is reprinted by permission form the Oklahoman and www.newsok.com.

Name Those Moons!

One day, some time before I retired as the director of the Kirkpatrick Planetarium of Science Museum Oklahoma, I was giving a talk to a group of students. After the talk, one of the students asked if I had ever discovered a constellation. Side note: constellations aren’t “discovered” as if they are a thing waiting to be found. They are pictures imagined in the stars, much like a cloud might look like a dog or a turtle. Every culture imagined such patterns in the stars, often quite different from those of any other culture. But, yes, I have imagined some of my own star pictures.

The point of her question, I believe, was whether I had ever made an astronomical discovery or, perhaps described and named some new phenomena. I have done both, but always after some else first discovered or named it, unbeknownst to me.

Now, you have an opportunity to do what I haven’t: be the first person to name a denizen of the astronomical zoo. Five moons of our largest planet, Jupiter, need names, and the International Astronomical Union (IAU), the governing body of all things astronomical, is giving the public the opportunity to name them.

Image Credit: International Astronomical League

But there are rules. The IAU has criteria for naming moons and other features on all the plants. IAU criteria for Jovian moons requires that Jupiter's moons be “after characters from Roman or Greek mythology who were either descendants or lovers of the god known as Jupiter (Roman) or Zeus (Greek).”

Any student of Greek or Roman mythology knows this leaves a lot of possibilities. Jupiter/Zeus was a rather randy deity. He had many lovers, and offspring by them, much to the consternation of his wife Juno/Hera.

Since Jupiter sits at the outer edge of the Asteroid Belt, it has many captured moons. Some orbit prograde, in the same direction that Jupiter rotates, but there are also many moons in a retrograde orbit, opposite the rotation. Moons in a prograde orbit must end in ‘a’ and retrograde moons must end in ‘e.’ Names can’t be too similar to other moon names, can’t be offensive in any language and can be no more than 16 characters long.

The Jupiter moon-naming contest ends April 15, so hurry. Details of the contest are at https://www.iau.org/news/announcements/detail/ann19010/.

On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission form the Oklahoman and www.newsok.com.

Jovian Dolphin

Jupiter dwarfs all the other planets in our solar system. More than one hundred planets the size of Earth could easily fit within Jupiter, below the cloud tops of the planet. The atmosphere of Jupiter holds a hurricane-like storm bigger than Earth that has been raging for hundreds of years.

 Lightning strikes in the giant planet’s atmosphere break methane into elemental carbon and oxygen. The carbon falls down into Jupiter’s atmosphere. Deep in the atmosphere, where pressure reaches thousands of times that at Earth’s surface, the carbon is squeezed into graphite, the material of pencil lead. Deeper still, the graphite is compressed into diamonds, which, unfortunately, melt as fall even deeper into Jupiter’s crushing atmosphere.

All this atmospheric turmoil creates colorful cloud patterns at the top of Jupiter’s atmosphere, perhaps the most colorful place in our solar system outside of a kindergarten art class. Who hasn’t gazed into the daytime sky and imagine shapes on the clouds? While you might imagine dragons or dogs, it’s not always easy to convince others of the same shape.

Jupiter’s atmosphere recently spawned an unmistakable cloud shape. Images of Jupiter reveal a Jovian dolphin swimming through the cloud bands on Jupiter. One might even imagine Flipper doing a tail-stand in the roiling Jupiter cloud sea.

For a series of images of the dolphin cavorting in Jupiter’s clouds, go to https://www.space.com/42672-dolphin-shaped-cloud-jupiter-juno-images.html.

On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.

Beaches. And Deserts and Sandboxes.

Perhaps you’ve heard this before: There are more stars in the universe than all the grains of sand in all the beaches, desserts and sandboxes on Earth.

There are a lot of sand grains on Earth. Sand constitutes a major fraction of the makeup of Earth. Scientists estimate the number by measuring the average size of a sand grains, then calculating how many sand grains it would take to fill, say, a gallon jug. Using the latest geological studies, they calculate the total volume of sand on Earth. Scientists estimate that Earth contains 7.5 sextillion sand grains. That is 75 followed by 17 zeros. That’s a lot of sand.

Astronomers calculate the total number of stars in the universe by studying nearby galaxies, ones in which we can count the stars, to see how many it takes to make a galaxy shine. Then, based on detailed counts of galaxies we can see, and making conservative estimates of how many we can’t see, they estimate the total number of stars in the universe. Our universe contains at least 70 septillion stars, 7 followed by 23 zeros.

Astronomers estimate there exist roughly 10,000 stars for each grain of sand on Earth. That’s a lot of stars.

Credit NASA-ESA

Astronomers recently discovered the origin of sand grains. For years, they believed that only sun-like stars created lots of carbon and silicon dust, and the silicon dust is the source of sand. That meant that the universe had to evolve to the point where there were lots of sun-like stars before lots of sand could accumulate. Recently, astronomers discovered the galaxies that formed very early in the universe, before many sun-like stars could form, contained a lot of dust. Long before stars like our sun were common, planets like Earth may have formed.

There may be a huge number of planets in our universe capable of supporting life.

On the first Tuesday of each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission form the Oklahoman and www.newsok.com.