“Troubled Waters”

A new wallpaper is up called “Troubled Waters” is available on the wallpaper page.  The planet Earth will outlast us all, it is we that swim in troubled waters. The only place in the cosmos that we know is hospitable to human life; we should be more careful in how we treat it and its inhabitants.

Troubled Waters

Till next time,

RC Davison

“Water Hole” – New Wallpaper Available

Check out the latest wallpaper, Water Hole, now up on the website.

Water Hole

Stop by the gallery and browse the other wallpapers that are available.

Till next time,

RC Davison

 

A Comet, a Moon and a Planet – a Tale of Two Tails

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Comet Catalina by Greg Hogan

Sometimes a picture captures just the right moment in space and time and shows us more than the obvious when we take a closer look. The great picture above, taken by Greg Hogan shows the comet Catalina visiting the morning sky with the crescent Moon and blazingly bright planet Venus. Focusing in on the wispy comet just left of center at the bottom of the image, one will notice that it looks more like a clock captured at five minutes before four. This image shows very nicely the two distinct tails that a comet can form as it dives into the inner solar system to swing around the Sun and back out again. The two tails accompanying a comet are distinctly different: one being a dust tail and the other an ion tail.

The coma or cloud around the head or nucleus of a comet, along with its tails start to form out around the orbit of Mars as the comet warms with the increasing amount of energy it’s receiving from the Sun. The comet is composed of ice (frozen gases, and water), dust, dirt and rock and is sometimes referred to as a “dirty snowball”. As it moves closer to the Sun it continues to heat up, and the ices begin to sublime or convert directly to a gas without going through a liquid phase. This release of gas carries dust particles with it, which destabilizes the comet’s surface allowing larger particles to be released, all of which contributes to the coma and tails. Intense jets of gas, can push even more material away from the comet. It is this debris trail that becomes the source for an annual meteor shower if and when the Earth crosses the path of the comet, such as the Perseids we see in the middle of August every year, which is from Comet Swift-Tuttle.

The dust tail reflects the sunlight and appears white in color similar to the coma. The dust is launched from the comet’s surface and slowly moves away from its host. These particles will begin orbiting the Sun on their own trajectory as they escape the gravitational influence of the comet. They are also pushed away from the comet by the radiation pressure from the Sun. This radiation pressure is due to the transfer of momentum from a light particle (photon) to the dust particle when they collide. This is exactly how a solar sail works. The dust tail will flow behind the comet and as the comet rounds the Sun the tail can become curved as the particles of dust are pushed by the light, as can be seen in the image below of comet McNaught.

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Comet McNaught’s dust tail – Image by Robert H. McNaught

The gas particles that are released by the comet will form the ion tail It is typically bluish/greenish in color and occurs because these gas particles liberated from the comet become “ionized” or charged by the high energy ultraviolet light emitted by the Sun. Once the atoms and molecules of gas become charged they will now be influenced by the magnetic field associated with the solar wind that comes from the Sun. The solar wind is a collection of high energy particles that the Sun radiates and entrained with this stream of particles is a magnetic field pointing away from the Sun. So the ion tail will point directly away from the Sun while the dust tail indicates the path the comet has taken. The ion tail can exhibit knots and twists due to the magnetic field as can be seen below.

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Comet Catalina’s twisted ion tail. Image courtesy of CometwatchUK

The  amazing image below shows comet Encke being buffeted by a coronal mass ejection (CME) from the Sun. The comet’s tail detaches as the mass of solar particles sweeps by and then quickly reforms. This is believed to be caused by the magnetic field retained in the CME interacting with the ion tail’s field. The video is from NASA’s STEREO solar mission.

Comet Encke’s interaction with a CME

If you look in Greg’s picture at the Moon you will see that it is illuminated on lower right hand side by the Sun, which is out of frame in the lower right. Now look closely at comet Catalina and at the “minute hand” of the clock – the ion tail; it’s pointing directly away from the Sun, while the “hour hand” – the dust tail is pointing more towards the Sun indicating that the comet is moving away from the Sun and heading back out of the solar system.  Catalina passed closest to the Sun on November 15, 2015 and will be closest to Earth on January 12, 2016.

Comet Catalina will make only a one-time appearance, as it has gained enough energy on its dive through the inner solar system that it will be jettisoned into interstellar space, never to return. On its journey it will pass through two large reservoirs of comets and other leftover debris from the early solar system that orbit our star, the Kuiper Belt and the Oort Cloud.

Comets originating in the Kuiper Belt, about 30 – 55 times the distance the Earth is from the Sun are known as short period comets, and have periods less than 200 years. Halley’s comet is a well known short period comet, having a period of about 76 years. Note that the Kuiper belt starts at the orbit of the planet Neptune. (Yes, Pluto is a Kuiper Belt object!) (The average Earth-Sun distance is 93 million miles or 150 million km and has been established as a standard unit of distance in astronomy known as an Astronomical Unit or “AU”.)

Long period comets originate from a much more distant region of the solar system, the Oort Cloud. This cloud of frozen debris extends from 5,000 AU to 100,000 AU. Way out there! These comets can have periods as long as 30 million years to complete an orbit around the Sun. Comet Catalina most likely originated from here.

Catch a glimpse of comet Catalina if you can in January, as it will be on the edge of naked-eye visibility, so under the right conditions you won’t need binoculars or a telescope, but they will make for much better viewing. Comets are relics of the early solar system and the more we can study them, the more we learn about how our place in space has formed.

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Jets on comet 67P from OSIRIS Imager on Rosetta – Image courtesy of the European Space Agency

Check out the European Space Agency’s site for amazing pictures and details on comet 67P (Churyumov-Gerasimenko) that their probe Rosetta has been flying in formation with for the last year.

Till next time,

RC Davison

References:

http://www.nasa.gov/sites/default/files/145944main_Kuiper.Belt.Lithograph.pdf

https://ase.tufts.edu/cosmos/view_chapter.asp?id=12&page=5

http://astronomy.swin.edu.au/cosmos/C/cometary+dust+tail

http://secchi.nrl.navy.mil/Publications/Vourlidas_encke_07.pdf

 

A Day With No Night – “Starry Night” Wallpaper

Most wallpapers evolve from an idea, or something I’ve seen during my daily journey through life.  Starry Night actually started out as a desert scene and ended up with water and a whole lot of suns in the sky.

Wallpaper - Starry Night

Starry Night

The vast majority of stars in the Universe are made up of red dwarf stars or class M stars.  They are smaller and cooler than our Sun and because of the fact that they are dimmer and cooler, they consume their hydrogen fuel at a much lower rate.  This means that these stars are very long lived – on the order of 10 trillion years, as compared to our Sun, which will be around for about 10 billion years.

Red dwarfs typically exist as solitary stars, but stars that are brighter than the red dwarfs tend to be found more commonly in binary configurations.  A binary star system has two stars that orbit around a common center of mass.  Stars can also exist in three, four or more configurations, but as you add more stars to the mix, the more unstable the system becomes.  Planets can form in such multi-stellar systems and several have been uncovered by the Kepler mission.

Starry Night is a multi-stellar system.  The most interesting thing that occurred to me was that the inhabitants on a planet in such a system may never have a night sky with which to peer into the depths of the Universe!  Imagine how much they would never know about the Universe.  And, even more interesting is to consider their response when they manage to rise above their atmosphere and glimpse the cosmos for the first time.

Enjoy Starry Night and visit the ORBITAL MANEUVERS web site for additional wallpapers and more.

Till next time,

RC Davison

Sunset at Wellesly Island – New wallpaper available

A sunset Inspired by a vacation in the Thousand Islands while staying on Wellesly Island, which overlooks the Lake of the Isles.  A beautiful area to appreciate some of the wonders this planet has to offer.

Wallpaper - Sunset at Wellesly Island

Sunset at Wellesly Island

Enjoy!

(Check out the other available wallpapers.)

Till next time,

RC Davison

“Life – Not as We Know It” — New Wallpaper

What’s out there?

Probably not bipedal, humanoid life with wrinkled foreheads, spotted faces and knobby noses so frequently depicted in modern sci-fi today.  What may be out there is probably more bizarre than we can imagine.  Take a look at what swims in our seas! (And, this is just what we know about.)  Just think about the fact that we — those creatures in the sea and us humans — all evolved on the same planet.  What is life going to be like that evolved on a different planet with different environmental stresses from what our evolutionary history has been? It probably tops anything we can imagine!

Below are two versions of the same scene depicting life on a watery planet, which exists near a sparkling globular cluster and nebula giving birth new stars.  My alien lifeforms are pretty tame, but the focus of the image was the environment and not the lifeforms.  The two versions are basically the same scene but with very different atmospheres and consequentially very different lighting effects.  I put both up for your viewing pleasure because I couldn’t make up my mind which version I liked better!  Let me know which one you prefer.

Wallpaper of

“Life – Not as We Know It” in blue.

Wallpaper -

“Life – Not as We Know It” in red

Check out more wallpapers at the Orbital Maneuvers website.

Till next time,

RC Davison

ORBITAL MANEUVERS Updated!

ORBITAL MANEUVERS has been updated with a bold new cover illustration and revised information in the Author’s Notes section on the latest efforts to identify and defend against Near-Earth Asteroid threats.

New OM Book CoverPlease note that the story has not changed, just the Author’s Notes section at the end of the book.  This section includes links to the latest efforts to identify Near-Earth Objects (NEOs) and our efforts to defend against a pending impact.  If interested, you can read this updated section of the book as it exists on the website on the Asteroids page.

The website also has an updated front page reflecting the new book cover and I’m intending on revising the site to be more compatible with the current mobile technology as time permits.

Stay tuned for more to come!  Thanks for the support!

Till next time,

RC Davison

Leonard Nimoy – A Man of Many Facets

Leonard Nimoy (1931 - 2015)

Leonard Nimoy (1931 – 2015)

     A human being portraying a fictional character that touched, if not inspired, millions for almost 50 years, Leonard Nimoy and Spock will be indelibly etched into history as one entity. A human actor who secured a role in 1966 as an alien aboard a starship with over 400 humans, Nimoy would eventually meld with this alien character to create the Vulcan, Spock we all know.

     Leonard Nimoy spent years trying to distance himself from the Vulcan after the original series ended, but he eventually learned that Spock was as much a part of himself as he was of the character. And, Spock, the half-human, half-Vulcan Science Officer on board the USS Enterprise was in constant turmoil with the emotions he felt and had to repress to be a Vulcan. Nimoy crafted a wonderful character whose internal conflicts could be intimately felt and shared by many of us across our planet Earth.

     Leonard Nimoy, a man of many talents: actor, director, producer, photographer, narrator, poet, musician, creator of Spock, will be missed. For whatever the Cosmos holds for you, live long and prosper and thank you for your inspiration.

Till next time,

RC Davison

Journey Far – New Wallpaper

Extraterrestrials, as portrayed by popular media, typically either want to eat our brains or strip the natural resources from our planet.  But, what if we are the technologically advanced civilization visiting a world that is just starting to be explored by its natives.  Will we be intelligent or civilized enough not to interfere with the planet’s inhabitants natural development?

The wallpaper Journey Far depicts explorers on distant planet leaving the shelter of their harbors and homes to discover the wonders their planet holds in store for them.

Wallpaper – Journey Far

Enjoy!

Till next time,

RC Davison

 

Asteroid 2004 BL86 Flyby on January 26, 2015 -Watch Out!

We will have a celestial visitor to our neighborhood on the 26th of January as asteroid 2004 BL86 passes by the Earth at a distance of about 745,000 miles (1.2 million kilometers). This is about three times the distance from the Earth to the Moon, so we don’t have anything to worry about—this time.

Asteroid 2004 BL86 Flyby – Image courtesy of NASA/JPL

But, what if it wasn’t missing us? What if it had a direct bead on Earth? What would we be doing today? Would Putin still be fanning the flames in the Ukraine? Would ISIL still be executing innocent people in their quest of world domination? Unfortunately, I think that the answer to these questions is probably yes – unless there was no doubt about 2004 BL86 landing in their back yard.

So, what would be the consequences of this asteroid hitting Earth?

First off, it’s not moving that fast—relatively speaking—56,520 km/h (35,120 mph), so it’s energy upon impact at about 6000 Megatons of TNT or 300,000 times the yield of the bomb dropped on Hiroshima, Japan (20 Kilotons of TNT). It could be a lot higher. (That’s a scary thought in its own right!)

The crater that would be left would be 4.7 miles (7.6 km) in diameter and have a depth of 1780 feet (544 meters) covering an area of (17.3 sq miles/45 sq km). The size of the crater alone would wipe out any major city on the planet, but the devastation would extend well beyond that from the fireball generated by the impact, high pressure atmospheric shockwave and seismic shock extending out to a distance of almost 60 miles (100 km). We are talking about tens of millions of people that will no longer exist in instant and millions more that will suffer from the after effects. (The numbers used here come from the calculator: Impact Earth.)

Remember, this is a small chunk of rock!

If it hit in the ocean, say a 100 miles (161 km) off a coastline in about 1000 feet of water, the tsunami waves generated could be between 29.2 feet (8.9 meters) and 58.4 feet (17.8 meters) high and would affect other coastlines around the world to a lesser degree. The size of the wave will change depending on where the asteroid hits the ocean relative to its depth and proximity to the coastlines.

The impact of 2004 BL86 wouldn’t end the world by any means, but it could kill many people and have global impact on international businesses and economies for years to come. The money that each country spends today on defense is money that should be spent on defending this planet from an impact that is surely to come sometime in the future—near or far. We are able to identify many of these objects as to the risks they pose to our planet, but we have not put forth a unified effort on preventing an impact should one be found coming our way. That technology is at hand but needs to be developed and refined.

Please note that the purpose of this exercise isn’t to scare people but to point out that Mother Nature has powers at her disposal that make our most formidable weapons pale in comparison, and the battles we fight on this spec of dust in the cosmos are insignificant. We’ve spent way too much time plotting against each other instead of planning a course of action that will benefit us all. Time marches on and we may be just running out of time to put up a good defense.

So, enjoy asteroid 2004 BL86 as it passes by—there will be plenty of media coverage—and be glad it’s not coming to stay permanently!

Till next time,

RC Davison