America celebrates its independence on every July 4th. Part of the celebration includes a multitude of fireworks in the night sky. In 1054 AD, another type of fireworks was witnessed by Chinese astronomers. According to their records, this new object appeared on July 4th. They called it a ‘guest star’. The object was visible for over two years in the night sky. For a period of 23 days the new star was even visible during the day. The Japanese and the Native American also recorded the new star. This object faded from the minds of humanity for over 700 years.
In 1758, Charles Messier located an object while he was tracking a comet. Messier decided to list this object and its location so others wouldn’t mistake it for a comet. He named it Messier 1. It was to become the first object on his list of 110 objects known today by amateur astronomers as the Messier list. Later it became known as the Crab Nebula due to its unusual shape.
Through photographs taken over a long period, astronomers noticed that the gaseous cloud was expanding. Tracing the expansion backwards, they discovered that this object was the one seen by the Chinese astronomers in 1054.
In the early 1960’s, radio telescopes picked up periodic signals from the sky. One of these objects gave off a periodic burst every 33 millisecond. At first, they were puzzled on what could spin this fast. After further investigation, the source was located where the Chinese astronomers saw the explosion in 1054 AD. The star was composed of only neutrons, and was about 17 miles in diameter. This type of star was named a pulsar. The spin was caused by the explosion of a massive star. What the Chinese astronomers had witnessed was a supernova, the violent death of a star.
With a telescope, anyone can view the remnant of the supernova. It looks like a pale whitish patch against the night sky. This ghostly remnant is all that remains from the ‘guest star’ first seen over 900 years ago.
Look to the west after sunset on the first to see Venus and Jupiter to be extremely close to each other. They will slowly separate from each other over the month.
Saturn will dominate the night time skies. It will be the brightest object to the right of the constellation Scorpius. If you have access to a telescope, try viewing its rings and its largest moon, Titian.
Mercury will be visible in the early morning hours during the first two weeks of July.
Though not visible, Pluto will be visited by the space probe New Horizon. It is scheduled to fly by on the 14. Visit NASA’s web site for the latest images.