9 Biggest Killers In Space

8. Runaway Celestial Bodies

What is it?

Runaway celestial bodies are not normally a commonality. Simply because of the energy it would take to keep an object the size of a small moon in motion without it breaking apart. However this does happen and has happened to Earth billions of years ago. It was actually an absolutely necessary cataclysmic event that needed to occur to bring about life on the planet. The prevailing theory is called the Giant Impact Hypothesis and demonstrates how a celestial body, roughly the size of Mars, impacted Earth - destroyed itself - and the resulting chunk that broke off became the moon. While the devastated planet (we live on) slowly formed from a molten ball of elements introduced from the impact, most of which was Iron.

Is this common? Can I hide under a table to survive?

As far as we know, it happened once about 4.5 billion years ago, during the early formation of this solar system. when most of the dust and gas forming around our sun was being pulled together by its gravity. Obviously, it has never happened again, but there are scenarios throughout the universe that could potentially lead to another rogue body impacting earth.

Has this happened before? Can it happen again?

Chances are this won't be happening again, the likelihood of a celestial body that size generally being thrown around is not common. However, the prevailing theories are based on the Moons throughout our solar system. Our moon, after impacting Earth helped stabilize the wild rotation our planet was undergoing. In the early formation of Earth, it's spin was roughly 4 hours per 360 degree rotation. Two hours daylight, and roughly two hours of night. After the impact, this rotation slowed down gradually to what it is today. Think of a ballerina doing a spin, if her arms are closed tight around her body, she spins very fast. If the Ballerina extends her arms outward, the spin is greatly slowed down. This is the same gravitational force or angular spin that affects our planet, in relation to the moon. We now live in a comfortable, for life to thrive, 24 hour rotation cycle. However, the moon is slowly moving farther and farther away. The earliest question that spawned the creation of calculus was "If an apple is effected by gravity and falls...does the moon also fall?" This is the question Isaac Newton asked himself, and literally invented Calculus to answer said question. Starting with the formula to measure the rate at which an object falls. While the moon is not actually "falling" toward Earth, it is "falling" away from the earth. Our spin is slowed by the shearing force of the moons gravity, which continually slows that spin. The rate at which the moon actually falls away is about 1 1/2 inches each year in increase to its orbital diameter. The calculations pinpointing the time when the moon will be at it's maximum distance from the earth is roughly around the same time as our Sun begins flaring out, increasing to the size of a Red Giant. What will actually happen to the orbit of the moon is debated. Some astrophysicists argue it will stabilize its orbit, others argue that the effects of gravity from the sun becoming a red giant will continue to affect its rate of departure. The same event has occurred to Venus (theoretically), yet there is no moon left remaining to suggest the event occurred similarly as it did on Earth. While this is a colossal "cosmic bullet", there is only one manner in which the universe likes to destroy celestial bodies with impacts from equal or larger celestial bodies on a more epic scale...