The more we look among the stars and galaxies, the weirder things seem to get.
Even space itself is puzzling, for example. Recent studies suggest that the fabric of the universe stretches more than 150 billion light-years across -- in spite of the fact that the cosmos is 13.7 billion years old.
From super-fast stars to the nature of matter, here we cover other strange and mysterious elements of the universe.
If you've ever gazed at the night sky, you've probably wished upon a shooting star (which are really meteors).
But shooting stars do exist, and they're as rare as one in 100 million.
In 2005, astronomers discovered the first "hypervelocity" star careening out of a galaxy at nearly 530 miles per second (10 times faster than ordinary star movement).
We have ideas about what flings these rare stars into deep space, but aren't certain; anything from off-kilter supernova explosions to supermassive black holes might be responsible.
Caption: Artist's rendition of a hypervelocity star leaving a galaxy. Credit: Harvard-Smithsonian Center for Astrophysics
Speaking of black holes, what could be stranger?
Beyond a black hole's gravitational border -- or event horizon -- neither matter nor light can escape. Astrophysicists think dying stars about three to 20 times the mass of the sun can form these strange objects. At the center of galaxies, black holes about 10,000 to 18 billion times heavier than the sun are thought to exist, enlarged by gobbling up gas, dust, stars and small black holes.
What about mid-sized types? Perhaps surprisingly, evidence is both scarce and questionable for their existence.
The sun spins about once every 25 days, gradually deforming its magnetic field.
Well, imagine a dying star heavier than the sun collapsing into a wad of matter just a dozen miles in diameter.
Like a spinning ballerina pulling his or her arms inward, this change in size spins the neutron star -- and its magnetic field -- out of control.
Calculations show these objects possess temporary magnetic fields about one million billion times stronger than the Earth's. That's powerful enough to destroy your credit card from hundreds of thousands of miles away, and deform atoms into ultra-thin cylinders.
Caption: Artist's rendition of a magnetar with magnetic fields shown. Credit: NASA
6. Dark Matter
5. Dark Energy
It might sound strange because we live on one, but planets are some of the more mysterious members of the universe.
So far, no theory can fully explain how disks of gas and dust around stars form planets -- particularly rocky ones.
Not making matters easier is the fact that most of a planet is concealed beneath its surface. Advanced gadgetry can offer clues of what lies beneath, but we have heavily explored only a few planets in the solar system.
Only in 1999 was the first planet outside of our celestial neighborhood detected, and in November 2008 the first bona fide exoplanet images taken.
Caption: Illustration of terrestrial, extrasolar planets. Credit: R. Hurt/NASA/JPL-Caltech
The force that helps stars ignite, planets stay together and objects orbit is one of the most pervasive yet weakest in the cosmos
Scientists have fine-tuned just about every equation and model to describe and predict gravity, yet its source within matter remains a complete and utter mystery.
Some think infinitesimal particles called gravitons exude the force in all matter, but whether or not they could ever be detected is questionable.
Still, a massive hunt is on for major shake-ups in the universe called gravitational waves. If detected (perhaps from a merger of black holes), Albert Einstein's concept that the universe has a "fabric" of spacetime would be on solid ground.
Caption: Artist depiction of gravity waves around merging black holes. Credit: NASA
The source of energy, matter and the universe itself is the ultimate mystery of, well, the universe.
Based on a widespread afterglow called the cosmic microwave background (and other evidence), scientists think that the cosmos formed from a "Big Bang" -- an incomprehensible expansion of energy from an ultra-hot, ultra-dense state.
Describing time before the event, however, may be impossible.
Still, atom smasher searches for particles that formed shortly after the Big Bang could shed new light on the universe's mysterious existence -- and make it a bit less strange than it is today.
Caption: Illustration showing the creation and expansion of the universe. Credit: NASA
Article posted October 31, 2008.