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Happy reading!
Yours,
Brandon Q. Morris
Also by Brandon Q. Morris
The Triton Disaster
Nick Abrahams still holds the official world record for the number of space launches, but he’s bored stiff with his job hosting space tours. Only when his wife leaves him, however, does he try to change his life.
He accepts a tempting offer from a Russian billionaire. In exchange for making a simple repair on Neptune’s moon Triton, he will return to Earth a multi-millionaire, enabling him to achieve his ‘impossible dream’ of buying his own California vineyard.
The fact that Nick must travel alone during the four-year roundtrip doesn’t bother him at all, as he doesn’t particularly like people anyway. Once en route he learns his new boss left out some critical details in his job description—details that could cost him his life, and humankind its existence…
3.99 $ – hard-sf.com/links/1086200
The Death of the Universe
For many billions of years, humans—having conquered the curse of aging—spread throughout the entire Milky Way. They are able to live all their dreams, but to their great disappointment, no other intelligent species has ever been encountered. Now, humanity itself is on the brink of extinction because the universe is dying a protracted yet inevitable death.
They have only one hope: The ‘Rescue Project’ was designed to feed the black hole in the center of the galaxy until it becomes a quasar, delivering much-needed energy to humankind during its last breaths. But then something happens that no one ever expected—and humanity is forced to look at itself and its existence in an entirely new way.
3.99 $ – hard-sf.com/links/835415
The Enceladus Mission (Ice Moon 1)
In the year 2031, a robot probe detects traces of biological activity on Enceladus, one of Saturn’s moons. This sensational discovery shows that there is indeed evidence of extraterrestrial life. Fifteen years later, a hurriedly built spacecraft sets out on the long journey to the ringed planet and its moon.
The international crew is not just facing a difficult twenty-seven months: if the spacecraft manages to make it to Enceladus without incident it must use a drillship to penetrate the kilometer-thick sheet of ice that entombs the moon. If life does indeed exist on Enceladus, it could only be at the bottom of the salty, ice covered ocean, which formed billions of years ago.
However, shortly after takeoff disaster strikes the mission, and the chances of the crew making it to Enceladus, let alone back home, look grim.
2.99 $ – hard-sf.com/links/526999
Ice Moon – The Boxset
All four bestselling books of the Ice Moon series are now offered as a set, available only in e-book format.
The Enceladus Mission: Is there really life on Saturn's moon Enceladus? ILSE, the International Life Search Expedition, makes its way to the icy world where an underground ocean is suspected to be home to primitive life forms.
The Titan Probe: An old robotic NASA probe mysteriously awakens on the methane moon of Titan. The ILSE crew tries to solve the riddle—and discovers a dangerous secret.
The Io Encounter: Finally bound for Earth, ILSE makes it as far as Jupiter when the crew receives a startling message. The volcanic moon Io may harbor a looming threat that could wipe out Earth as we know it.
Return to Enceladus: The crew gets an offer to go back to Enceladus. Their mission—to recover the body of Dr. Marchenko, left for dead on the original expedition. Not everyone is working toward the same goal. Could it be their unwanted crew member?
9.99 $ – hard-sf.com/links/780838
Proxima Rising
Late in the 21st century, Earth receives what looks like an urgent plea for help from planet Proxima Centauri b in the closest star system to the Sun. Astrophysicists suspect a massive solar flare is about to destroy this heretofore-unknown civilization. Earth’s space programs are unequipped to help, but an unscrupulous Russian billionaire launches a secret and highly-specialized spaceship to Proxima b, over four light-years away. The unusual crew faces a Herculean task—should they survive the journey. No one knows what to expect from this alien planet.
3.99 $ – hard-sf.com/links/610690
The Hole
A mysterious object threatens to destroy our solar system. The survival of humankind is at risk, but nobody takes the warning of young astrophysicist Maribel Pedreira seriously. At the same time, an exiled crew of outcasts mines for rare minerals on a lone asteroid.
When other scientists finally acknowledge Pedreira’s alarming discovery, it becomes clear that these outcasts are the only ones who may be able to save our world, knowing that The Hole hurtles inexorably toward the sun.
3.99 $ – hard-sf.com/links/527017
Silent Sun
Is our sun behaving differently from other stars? When an amateur astronomer discovers something strange on telescopic solar pictures, an explanation must be found. Is it merely artefact? Or has he found something totally unexpected?
An expert international crew is hastily assembled, a spaceship is speedily repurposed, and the foursome is sent on the ride of their lives. What challenges will they face on this spur-of-the-moment mission to our central star?
What awaits all of them is critical, not only for understanding the past, but even more so for the future of life on Earth.
3.99 $ – hard-sf.com/links/527020
The Rift
There is a huge, bold black streak in the sky. Branches appear out of nowhere over North America, Southern Europe, and Central Africa. People who live beneath The Rift can see it. But scientists worldwide are distressed—their equipment cannot pick up any type of signal from it.
The rift appears to consist of nothing. Literally. Nothing. Nada. Niente. Most people are curious but not overly concerned. The phenomenon seems to pose no danger. It is just there.
Then something jolts the most hardened naysayers, and surpasses the worst nightmares of the world’s greatest scientists—and rocks their understanding of the universe.
3.99 $ – hard-sf.com/links/534368
Mars Nation 1
NASA finally made it. The very first human has just set foot on the surface of our neighbor planet. This is the start of a long research expedition that sent four scientists into space.
But the four astronauts of the NASA crew are not the only ones with this destination. The privately financed ‘Mars for Everyone’ initiative has also targeted the Red Planet. Twenty men and women have been selected to live there and establish the first extraterrestrial settlement.
Challenges arise even before they reach Mars orbit. The MfE spaceship Santa Maria is damaged along the way. Only the four NASA astronauts can intervene and try to save their lives.
No one anticipates the impending catastrophe that threatens their very existence—not to speak of the daily hurdles that an extended stay on an alien planet sets before them. On Mars, a struggle begins for limited resources, human cooperation, and just plain survival.
3.99 $ – hard-sf.com/links/762824
A Guided Tour of Comets
It was a coincidence that Rosetta specifically visited the 67P comet, named Churyumov-Gerasimenko after the astronomers who discovered it. This coincidence provided scientists with an exciting research project—and us with beautiful photos.
A comet is a celestial body which, when its orbit nears the sun, develops a coma and usually a glowing tail. The name comes from ancient Greek κομήτης (hair star), derived from κόμη (‘hair of the head’ or ‘mane’).
How typical is 67P when compared to its countless siblings? How are they formed, where do they come from, and what becomes of them? These questions are answered in the following biography.
Classification and naming
Comets are divided into periodic and non-periodic, depending on the interval between their appearances, and the former is divided additionally into long-period and short-period.
Periodic comets are those whose return is ascertained by measuring their course, that is, those that circle the sun in a stable orbit—at least for a certain period of time. In principle, non-periodic comets don’t return, due to their parabolic or hyperbolic courses.
Long-period comets, with an orbital period of more than 200 years, are presumed to come from the Oort cloud at the edge of the solar system. Their orbital inclinations are statistically distributed across the entire solar system, whereas the planets all move, roughly speaking, along the same plane around the sun. Sometimes they orbit the sun in the same direction as the planets (prograde), but sometimes in the opposite direction (retrograde). Their orbital eccentricities are close to 1, meaning they are very elongated ellipses. Long-period comets are generally still bound by the sun’s gravity, although they may sometimes need up to 100 million years to complete an orbit!
Eccentricities larger than 1 (hyperbolic courses) are rare for comets—which is logical, as we never see these comets again because they are non-periodic comets that leave the solar system. The reason for this is usually a disturbance in their orbit when passing the large planets. However, minor influences in the outer region of the planetary system are sufficient to give an orbit an elliptical shape again. Around 10 to 20 comets with a hyperbolic course are discovered each year.
Short-period comets with orbital periods of less than 200 years often originate from the Kuiper belt in which the dwarf planet Pluto moves. They typically orbit in the direction of the sun’s rotation. Their orbital inclination is around 20 degrees on average, meaning their orbits are close to the ecliptic—the level of the planetary orbits.
More than half of all known short-period comets belong to the ‘Jupiter family,’ and their furthest distance from the sun is not in the Kuiper belt but near Jupiter’s orbit—that is, five to six astronomical units (AUs). 67P/Churyumov-Gerasimenko is one of these. The time it takes to orbit the sun is only 5 to 11 Earth years. Scientists believe it was originally a long-period comet, the orbit of which was changed by the gravitational influence of the giant planets.
How did it come to be named ‘67P/Churyumov-Gerasimenko?’ A newly discovered comet first receives a designation from the International Astronomical Union, consisting of the year of its discovery and an uppercase letter corresponding to the date of discovery—beginning with A from January 1, B from January 16, in a bi-monthly rhythm (up to Y from December 16, and skipping the letter I). And then there’s another number added to differentiate it from other comets found in the same half-month. So 67P was initially called 1969 R1, having been the first comet discovered in the first half of September (R) 1969.
As soon as the orbital elements of the comet have been more precisely determined, the name is prefixed with another letter according to the following system:
P: The orbital period is shorter than 200 years, or there have been at least two confirmed observations of its perihelion past the sun (periodic comet)
C: The orbital period is longer than 200 years
X: The orbit is unable to be determined
D: A periodic comet that went missing or no longer exists
A: Subsequently established to be an asteroid and not a comet
I: Interstellar—the comet did not originate in our solar system
Comet Hyakutake, for example, is also known as C/1996 B2. Hyakutake was the second comet discovered in the second half of January 1996. Its orbital period is longer than 200 years.
Comets are also typically named after the people who discover them. For example, D/1993 F2 is also known as Shoemaker-Levy 9—the ninth comet that Eugene and Carolyn Shoemaker discovered together with David H. Levy.
If a comet is observed passing the sun a second time, it usually receives a fixed number and a name. And that’s how it happened for P/1969 R1. It was given the number 67P and the names of its discoverers Klim Churyumov and Svetlana Gerasimenko. Gerasimenko took the photo in which Churyumov later discovered the new comet.
The number of newly discovered comets was around 10 per year up to the 1990s, and since then, it has increased considerably through the use of automatic search programs and space telescopes. Most new comets, and those observed in earlier orbits, are only visible through a telescope. When they approach the sun they begin to shine more brightly, but the development of this brightness and the tail can’t be precisely predicted. Truly impressive appearances only happen about every 10 years.
The structure of comets
The nucleus
At vast distances from the sun, comets only consist of a nucleus. They are primarily made of water ice, dry ice (CO2), CO ice, other frozen substances such as methane and ammonia, and admixtures of small dust and mineral particles (for example, silicates or nickel-iron). That’s why comets are often called ‘dirty snowballs.’ However, the observations of the Deep Impact mission have shown that (at least in the outer area of the nucleus of the examined comet, Tempel 1), the proportion of solid materials can outweigh the volatile elements, so that ‘icy dirtball’ seems more apt.
We know from the Giotto space probe’s observations of Halley’s Comet that comets are typically surrounded by a black crust, which only reflects around four percent of light. Although comets can be observed in the sky as spectacular light displays, their nuclei are among the blackest objects in the solar system. By comparison, asphalt reflects approximately seven percent of light.
Since only small regions of the nucleus outgas, it is now assumed that the surface is formed out of a kind of rubble, consisting of rock fragments too heavy to overcome the gravitational attraction of the nucleus, and thus unable to fly away. Giotto also discovered tiny particles rich in the elements carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), also called CHON particles. These could originate from a thin layer of soot covering the surface of the nucleus, which would explain the low reflectivity.
The coma
As soon as a comet approaching the sun crosses Jupiter’s orbit at a distance of about five AU, the comet’s interaction with the solar wind causes a bowl-shaped ‘coma,’ which shows radiation-like structures near the nucleus. It arises because volatile substances on the side facing the sun sublimate (i.e., change from a solid state to a gaseous state) and carry off dust particles embedded in the ice. According to the observations of the Giotto probe, this sublimation only occurs on about 10 to 15 percent of the surface of the comet. Volatile substances only appear to be released from brittle points on the black crust. Molecules released at these points form the inner coma.
Through further heating, ionization, and the tearing of molecules (dissociation), the coma continues to grow, finally forming the coma we can see, from ions and groups of molecules. It is surrounded by a halo of atomic hydrogen radiating in ultraviolet, called a UV coma, which on Comet Hale-Bopp in 1997, for example, reached a diameter of 150 million kilometers. Since the Earth's ozone layer blocks UV radiation, the UV coma can only be examined from space.
The tail
The coma’s components are ‘blown away’ by solar wind and radiation pressure coming from the sun, forming a tail, typically inside the orbit of Mars—or to be more precise, two tails that can point in different directions:
a narrow, elongated tail (type I tail), primarily consisting of molecular ions, always pointing away from the sun, called a plasma tail, typically blue, and the prettier of the two
a diffuse, curved tail made of dust particles (type II tail), also called a dust tail
How large the two tails become depends on how much material the comet releases, and how close it comes to the sun. But how well we can see them in the sky depends more on the relative positions of the Earth and the comet. If we’re unlucky, we don’t see the more beautiful tail because we’re looking at the comet front-on.
Why is the dust tail curved? Small dust particles that form the dust tail are primarily influenced by radiation pressure from the sun. This has two components:
The first, the radial component, is directed against gr
avity and decreases quadratically as the distance to the sun increases. For the dust particles, this effectively feels like a reduction in solar gravitational force. Therefore they move along their own course (‘pseudo-Kepler orbits’), which is also differentiated for different-sized particles, as radiation pressure is dependent on particle size. This leads to a relatively intense fanning out of the dust tail in comparison to the plasma tail.
A second component of radiation pressure is directed against the direction of movement of the dust particles, and therefore decelerates all those particles that are larger than the wavelength of the radiation (about 0.5 µm). In the long term, these particles move in the same way as other interplanetary dust, spiraling toward the sun.
An antitail (type III tail) is only visible in special orbit configurations. However, this isn’t a discrete tail, but rather a geometric projection effect. When the Earth moves between the sun and the comet, part of the dust tail appears to protrude beyond the comet’s nucleus, due to its curvature. The antitail can then appear to be pointing toward the sun.
The Dark Spring: Hard Science Fiction Page 27