Just How Much Cosmic Dust falls to Earth Each Year?

 

On almost any dark, clear night away from city light pollution, even the casual sky observer may see one or several “shooting stars.” Tiny bits of rock, typically less than an inch across, create these brief streaks of light. The rocky bits move so quickly through the air that they create a huge amount of friction, heating the air to incandescence which creates the streak of light.

Eventually, the cosmic rock is broken into tiny dust particles which float serenely down to the surface of our planet. This cosmic dust comes primarily from two sources. A research team studying this phenomenon, led by Julien Rojas, a doctoral student at the University of Paris–Saclay, found that more than 60% of the dust originates from the family of comets that Jupiter’s huge gravitational pull herds into orbits of less than 20 years and which can pass close to Earth’s orbit. Another 20% of the dust likely came from the main asteroid belt.

                          Meteor entering Earth atmosphere as seen from the ISS. Credit NASA

Astronomers want to know just how much of this cosmic dust Earth accumulates each year. But the problem is that with dust constantly blowing around all over our planet, it becomes virtually impossible to separate space dust from Earthly dust.

There is one place where terrestrial dust does not contaminate extraterrestrial dust, Antarctica. The study team collected ice cores from that continent in an attempt to quantify the amount of cosmic dust landing on our planet each year. And, because the snow and ice cover there can be melted, it is easy to separate the tiny dust particles from the otherwise dustless environment. Jean Duprat, a cosmo-chemist and co-author of the study, said “The South Pole is by far the best location because you are surrounded by oceans, you are completely isolated from mainlands.”

 Extrapolating the three-year study of Antarctic cosmic dust measurements to the entire planet, the team found that between 4,000 and 6,700 metric tons of space dust falls to Earth each year. Rojas explained that the study’s range is simply a matter of statistics due to the inherent difficulty of extrapolating the worldwide accumulation from a series of limited, local measurements. “Depending on the volume of snow,” Rojas said, “you would expect a certain uncertainty by just counting the particles.”

Between 4,000 and 6,700 tons a year! And you think you have a problem keeping weight off.

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.

 

Is the Hypothesized "Planet Nine" Actually a Primordial Black Hole?

 On March 13, 1781, astronomer William Herschel pointed his telescope into the night sky and discovered the planet Uranus, the first such discovery in historical times. Over the next 45 years, as astronomers observed Uranus looking for possible moons, they realized its orbit didn’t follow the known laws of gravity. Some astronomers surmised that perhaps Newton’s gravitational laws didn’t work so far from the sun.

But two mathematicians decided that the discrepancy occurred due to the gravitational attraction of an eighth planet even farther out. Unbeknownst to each other, both French astronomer Rubin Le Perrier and British mathematician John Couch Adams began calculating the likely position of such a planet based on the aberrations of the orbit of Uranus. On September 23, 1846, French astronomer Johanne Galle found Neptune within one degree of the predicted position. The effect of Neptune’s gravitational pull on the orbit of Uranus led to its discovery.

In January 2015, Caltech astronomers Konstantin Batygin and Mike Brown noted some rather odd orbits of five asteroids in the far outer regions of our solar system. Using computer modeling, they predicted the presence of a ninth planet ten times larger than Earth whose gravity they theorized affected the asteroids. They dubbed it “Planet Nine.”

That planet has never been discovered even with today’s sophisticated telescopes, yet according to Brown and Batygin, new evidence continues to support their hypothesis. This negative result has led some astronomers to propose a radical idea: maybe the cause of the odd orbits isn’t a large planet but rather a small black hole.

Typically, black holes result from the death of massive stars and are typically five to ten times the mass of our sun. But the extreme conditions at the earliest stages of the formation of the universe could have created smaller, planet-sized black holes, called primordial black holes, although we’ve yet to find any. 

Primordial black holes may exist throughout the cosmos. Credit NASA

A planet ten times the size of Earth should have been found, many astronomers believe, but a black hole of the same mass would be tiny and impossible to see. The only way to discover one is to use the same method astronomers use to find any stellar-sized black hole, by way of its massive gravity. A planet-sized black hole might be invisible, but the gravity of one could certainly cause the observed effect.

I think the idea of a primordial black hole at the edge of our solar system is exciting. As long as it stays out there.

Is There Life on Mars? Maybe, but We Haven't Looked in the Right Places

 Two new studies point to a real possibility of life on Mars. We know Mars once had lots of water, enough water to cover the entire planet by as much as three-quarters of a mile. That water is now lost from the surface.

                          Artist’s rendering of Mars before it lost surface water, credit NASA

One study, led by Eva Scheller, a planetary scientist at the California Institute of Technology, looked at the rate at which Mars lost water to space. Hydrogen, a component of water molecules, comes in various forms. Normal hydrogen consists of one proton and one electron. Deuterium, also called heavy hydrogen, also contains one neutron. Being heavier, deuterium can’t escape Mars as easily as normal hydrogen. By studying the ratio of the two, scientists can determine how much hydrogen, and therefore water, Mars lost to space since it formed. This allows the scientists to estimate the total amount of water Mars originally possessed.

Since the rate of hydrogen loss early in Mars’ history can’t be known precisely, scientists can only estimate the amount of water lost. They calculate that the total amount of water lost from Mars amounts to only enough to cover the planet by up to 82 feet. That leaves a lot of water still on Mars. The rest, they claim, went underground, chemically combined with minerals in the Martian crust. "Mars basically became the dry, arid planet we know today 3 billion years ago," Scheller stated. Since then, the amount of water locked below the crust has remained essentially unchanged. Water loss from Mars stopped when the remaining water became trapped in the crust.

                                                  Mars with polar ice cap, credit NASA

Nathalie Cabrol, director of the Carl Sagan Center for Research, part of the SETI Institute, led the second study. She claims life would still exist on Mars if it ever developed there. It simply would have moved underground with the water. We haven’t found it yet because we haven’t looked in the right places.

Cabrol studies some of the harshest environments on Earth, locations scientists refer to as Mars analogs. These places represent the environments on Earth most like Mars, a cold, dry desert world. She explains that at these locations on Earth, “You can walk on the same landscape for miles and find nothing. Then, maybe because the slope changes by a fraction of a degree, the texture or the mineralogy of the soil is different because there is more protection from UV, all of a sudden, life is here.”

On Earth, virtually everywhere water exists, so does life, even deep below ground with water trapped in rocks. Cabrol says that on Mars, other conditions must also be considered. “What matters in extreme worlds to find life is to understand the patterns resulting from these interactions.”

Both scientists agree that the Perseverance Rover, newly landed on Mars, may be able to find the right conditions for Martian life below the surface.

 

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.

 

Is Earth Soon Due for a Mass Extinction?

 

Earth’s magnetic field does more than makes compasses point north. It also protects us against dangers from space, specifically solar wind and cosmic rays. Without our protective magnetic shield, the solar wind could strip away much of our atmosphere, as occurred on Mars. As the atmosphere diminishes, the oceans slowly evaporate and become lost to space, as on Mars.

Earth’s hot, liquid-iron interior generates our magnetic field. The liquid core of Earth gets so hot that electrons are stripped off the molecules. As the charged particles spin around with Earth’s rotation, it generates our lifesaving magnetic field. But, Mars, being smaller, cooled long ago, the core solidified, and it no longer generates a magnetic field, hence its cold, dry, virtually lifeless surface.

Earth's magnetic field. Credit Nasa

Earth’s magnetic field isn’t as stable as it might seem. Over long periods of time, it flips with magnetic north and south poles reversing. During that magnetic flip, the magnetic field can become significantly weaker.

Such a magnetic pole reversal occurred 42,000 years ago. Researchers of the University of New South Wales studied the event. Chris Turney, a co-author of the study, explained “Earth’s magnetic field dropped to only 0 to 6% strength during the event. We essentially had no magnetic field at all. Our cosmic radiation shield was totally gone.” That event coincided with the extinction of many species, including the Neanderthals. Scientists are still trying to work out just how much the reversal affected those now-extinct species.

Although such magnetic reversals generally occur on timescales of a few hundred thousand years, geoscientists have found ample evidence that such a reversal may already be underway. Pole wandering, or the movement of the magnetic poles, is more pronounced than in the past. Over the last 170 years, Earth’s magnetic field strength has decreased by 9%.

At the very least, a severely weakened magnetic field can cause total malfunction of communications and all other satellites and will be dangerous, perhaps even lethal, to any astronauts. At its worst, it could dramatically increase animal extinctions and severely affect human health. No one can say for sure if or when a magnetic reversal will occur, how long it might take, and how long it would last. But, the geologic record paints a potentially grim picture.

 

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.

A Review of my book "If You Swallow That Seed"

 

If You Swallow That Seed
Written by Wayne Harris-Wyrick
Illustrated by Matthew Hughes
Published by 4RV Publishing, 2015

Review By Kena Sosa

 

Parents say the weirdest things. In the case of the story, If You Swallow That Seed, a mother’s words literally sprout into action. The main character is shocked to find carrots growing out of his ears after swallowing a seed just as his mother warned him. He puts the carrots to good use feeding horses, but before he can overcome his problem, his mother has even more wacky comments to say and they all come true!

The boy shows determination time and time again, finding solutions to the weirdness until it gets out of hand. Matthew Hughes’ illustrations are full of texture, adding dimension and additional flavor to the story, especially in the cover illustration where we see the boy and his horses enjoying their role in the adventure.

Kids will get a kick out of this story and connect with it as they’ve been confused by their own parent’s idioms and sayings. A story that feels straight out of the childhood of the author, Wayne Harris-Wyrick, this book takes it further than just one metaphor. Swallowing the first seed is only the beginning of the adventure of what happens when words are taken literally. It is packed with excitement, fun and a great segway into the silly and savvy world of idioms and sayings.

Reprinted by permission of the author.

 

Book Review: Forty Winks

 

Book Review: Picture book Forty Winks

Written by Nancy Allen

Illustrations by Diane Brown

 

 

Generally, picture books for kids have one of two primary purposes: to entertain or to inform. While these two ideas don’t begin to cover all the variations in picture books, virtually all picture books articulate these two qualities in some proportion.

 Virtually all children’s books have a moral or help the child reader understand good choices. The best children’s books both teach and entertain. In Forty Winks, Nancy Brown offers what seems, on the face of it, a bedtime story to entertain young readers. Joey has trouble getting to sleep. Although he tries some methods to bring on sleep, his imagination keeps him from becoming drowsy. That is until he meets Sir Nod, a book-loving monster living in his closet.

 Sir Nod shows Joey his “magical book.” “Read it,” Sir Nod says, “ and you can travel anywhere,” then immediately falls asleep. Joey takes the book and reads a story about a pirate adventure, but is soon fast asleep, dreaming about pirates.

Joey wants to keep the book, but Sir Nod cries that it is his only book. Nod tells Joey he can read his own books, but Joey complains that his books aren’t magical. Sir Nod replies, “The magic happens when you read a book.” Joey and Sir Nod settle their disagreement about using the book and come to a mutual, and sleep-inducing, solution.

 As is common with picture books published by 4RV Publishing, the book contains an appendix with discussion questions and extra “fun facts.” Here, Nancy Allen continued her mix of entertainment and information.

 Diane Brown’s illustration nicely captured Joey’s adventures on a pirate ship, traveling through space, and more. These illustrations will trigger the imagination of young readers just as well as the story does.

 This book may help a child go to sleep, but even better, it encourages children to experience the magic of books. I applaud any book that encourages children to read, whether or not it helps them sleep.

4RV Authors, Artists, and Editors Awarded

 Among other things, I write books for children. I have five published books with three more in the works at my publisher, 4RV Publishing. The name has nothing to do with recreational vehicles. When the publisher/president started the company, she used the initials of the members of her family: four R’s and a V. You can see all the books (including mine!) and authors at 4RVPublishing.com.

 

 Every year, www.critters.org publishes the Critters Readers Poll on the best in writing for the previous year. Formerly known as “Predators and Editors,” this poll has been published for 25 years. Readers vote on their favorites in forty-five categories including twenty-five genres of novels and short stories, artists, covers, online bookstores, and other areas related to publishing. The most recent winners and runners-up can be found at http://critters.org/predpoll/final_tally.ht.

 This year, 4RV books and editors won several awards, including two First Place awards, six Second Place awards, and one Sixth Place award.

These awards demonstrate the excellence of this small press publisher and care with which the publisher’s president, Vivian Zabel (the “V” in 4RV) selects the editors and the books they publish.

 Congratulations to Cheryl Malandrinos, Jeanne Conway, Vivian Zabel, D. K. Davenport,  Shawn Simon, Rita Durrett and 4RV Publishing!