In the 20th century Earth sent probes, transmissions, and welcoming messages to the stars. Unfortunately, someone noticed. The Galactics arrived with their battle fleet in 2052. Rather than being exterminated under a barrage of hell-burners, Earth joined their vast Empire. Swearing allegiance to our distant alien overlords wasn't the only requirement for survival. We also had to have something of value to trade, something that neighboring planets would pay their hard-earned credits to buy. As most of the local worlds were too civilized to have a proper army, the only valuable service Earth could provide came in the form of soldiers....

Welcome to Ringworld, an intermediate step between Dyson Spheres and planets. The gravitational force created by a rotation on its axis of 770 miles per second means no need for a roof. Walls 1,000 miles high at each rim will let in the sun and prevent much air from escaping. Larry Niven's novel, Ringworld, is the winner of the 1970 Hugo Award for Best Novel, the 1970 Nebula Award for Best Novel, and the 1972 Ditmars, an Australian award for Best International Science Fiction.

Kyle Riggs is snatched by an alien spacecraft sometime after midnight. The ship is testing everyone it catches and murdering the weak. The good news is that Kyle keeps passing tests and staying alive. The bad news is the aliens who sent this ship are the nicest ones out there.

They hunt us. They bomb our worlds for target practice. A star cluster in the constellation of Orion rotates once every 1,000 years. Those who rule there have an ancient tradition: When each cycle ends, they train their fleets by spilling the blood of lesser beings. The enemy fleets are coming again. In response, the Rebel Worlds gather their starships to face the terrifying threat, and this time humanity is asked to stand with them. The last time they considered Earth, Vikings in longboats were raiding English coastlines. Today, we're less primitive. Today, we're a target.

The war raged across the galaxy. Billions had died, billions more were doomed. Moons, planets, the very stars themselves, faced destruction, cold-blooded, brutal, and worse, random. The Idirans fought for their Faith; the Culture for its moral right to exist. Principles were at stake. There could be no surrender. Within the cosmic conflict, an individual crusade. Deep within a fabled labyrinth on a barren world, a Planet of the Dead proscribed to mortals, lay a fugitive Mind. Both the Culture and the Idirans sought it....

Predator ships stream into human space in unprecedented numbers. The Colonial Marines, controlled by Weyland-Yutani, respond to the incursion, thus entering the Rage War. This terrifying assault by the Yautja cannot go unchallenged, yet the cost of combat is high. Predators are master combatants, and each encounter yields a high body count. Then, when Lt. Johnny Mains and his marines - the VoidLarks - enter the fray, they discover an enemy deadlier than any could imagine.

On June 30, 1908, an object fell from the sky, releasing more energy than a thousand Hiroshima bombs. A Siberian forest was flattened, but the strike left no significant crater. The anomaly came to be known as the Tunguska Event, and scientists have never agreed whether it was the largest meteor strike in recorded history - or something else. Alien artifacts have been uncovered since the 1908 event, and a new star drive is discovered.

As a child Chris Hooper dreamed of monsters. But in deep space, he found only darkness and isolation. Then, on planet LV178, he and his fellow miners discovered a storm-scoured, sand-blasted hell - and trimonite, the hardest material known to man. When a shuttle crashes into the mining ship Marion, the miners learn that there was more than trimonite deep in the caverns. There was evil, hibernating - and waiting for suitable prey.

The Earth died when aliens rained thermonuclear warheads on her cities and sprayed the surface with a bio-terminator. A deadly poison drifted to every corner of the planet, threatening the last survivors with annihilation. For a soldier like Creed, there is only one way to keep breathing untainted air. He must bury his hatred of the extraterrestrials and join the Jelk Corporation as an assault trooper, leaving the planet for outer space. In return for his and other people's services, the corporation will house the last humans for as long as the assault troopers keep winning.

"Triplanetary" is a science fiction novel and space opera by author E. E. Smith, published in 1948. It consists of two parts. The first explains the series background, which consists of a conflict between the evil Eddorians and the benevolent Arisians. This conflict is carried out throughout the history of an oblivious humankind on Earth. The final part of the book, which was originally published as a magazine story, takes up the tale after civilization has been rebuilt.

They came from the brightest star in the southern constellation of Carina. First they studied us. Now they're among us, threatening human existence as they search for the Starcore, the greatest device of the lost Polarions. Logan is captured in the Nevada desert but escapes in Greenland. There he finds an extraterrestrial stealth ship, giving him the means to take the battle to the enemy.

Deathworld centers on Jason dinAlt, a professional gambler who uses his somewhat erratic psionic abilities to tip the odds in his favor. He is challenged by a man named Kerk Pyrrus (who turns out to be the ambassador from the planet Pyrrus) to turn a large amount of money into an immense sum by gambling at a government-run casino. He succeeds and survives the planetary government's desperate efforts to steal back the money.

AD 2457. The longest space voyage in history has begun: 230 light years from a ravaged Earth to the pristine star system of New Eden - a beacon of hope following the Doom Star days. Aboard the ship are human colonizers, the Space Navy, fierce “Monitors” once bred to fight Cyborgs, and four “Specials” - humans with psionic abilities, capable of ripping holes in space to jump vast distances.

In the mid-23rd century, Darwin, Australia, stands as the last human city on Earth. The world has succumbed to an alien plague, with most of the population transformed into mindless, savage creatures. The planet’s refugees flock to Darwin, where a space elevator—created by the architects of this apocalypse, the Builders—emits a plague-suppressing aura.

Moth was a beautiful planet, the only one with wings - two great golden clouds suspended in space around it. Here was a wide-open world for any venture a man might scheme. The planet attracted unwary travelers, hardened space-sailors, and merchant buccaneers - a teeming, constantly shifting horde that provided a comfortable income for certain quick-witted fellows like Flinx and his pet flying snake Pip.