Planetary alignment of Venus, Mercury, and Saturn with the Giza Pyramids in Egypt. This phenomenon only happens once every 2,373-years and the next event is set for December 3, 2012, at one-hour before sunrise.
This Mind-Blowing Planetary Alignment Happens Once Every 2373-Years
The Largest Galaxy in the Observable Universe? The spectacular barred spiral galaxy NGC 6872 has ranked among the biggest stellar systems for decades. A team of astronomers from the United States, Chile and Brazil have crowned it the largest-known spiral. Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way.
Stellar Ripple Approximately 100 million years ago, a smaller galaxy plunged through the heart of the Cartwheel galaxy, creating ripples of brief star formation. In this image, the first ripple appears as an ultraviolet-bright blue outer ring so powerful that it may be one of the most powerful UV-emitting galaxies in the nearby universe.
Gravity Waves Gravity waves are distortions in the fabric of space-time predicted by Albert Einstein's theory of general relativity. The gravitational waves travel at the speed of light, but they are so weak that scientists expect to detect only those created during colossal cosmic events, such as black hole mergers like the one shown above. LIGO and LISA are two detectors designed to spot the elusive waves.