The moon shines by acting like a mirror and reflecting the light from the sun towards earth. As the moon orbits the earth, sometimes the moon will pass into the shadow of the earth cast by the sun, as the sun earth and moon line up in space. When this happens, observers on earth experience a dimming of the moon. This is a lunar eclipse. There are three different types of lunar eclipses. A total lunar eclipse, a partial lunar eclipse and a penumbral lunar eclipse.
At the start of the 20th century an Italian by the name of Marconi began experimenting with wireless telegraphy. Soon after, wireless telephony and radio broadcasting were developed. Since those early days, humans have been pumping out radio, television and communications signals from our planet in an ever increasing quantity and strength.
Like a wave that travels outward when a stone is thrown into water, radio and TV signals travel by electromagnetic wave at the speed of light in an ever expanding sphere away from the earth. Theoretically, anyone with a powerful enough receiver on another planet would be able to eavesdrop on us. So how likely is this, and if they are listening, are they coming to visit?
Step outside on On Monday the 14th November just after sunset and look to the north east and you will see a large moon rising (assuming it is clear). Looks huge, right? Much bigger than normal? Lots of reports in the media about this massive supermoon and how the full moon won’t appear this big again until 2034. But what exactly is a supermoon and is it rare?.
Last week scientist announced that the amount of galaxies in the universe had been underestimated by as much as a factor of 20. Major news, but not something that really affects our daily lives. The discovery does however, illustrate the vast scale of our universe. Thankfully, we as humans have developed the brain capacity, the intelligence and the curiosity to help us understand our place within it. Take for example the speed of light. It travels at 300,000 km per second. Pretty much instantaneous for us on earth, but really noticeable in the realm of the galaxies, stars and planets. Light from the moon takes little over a second to reach us, whilst light from the sun takes over 8 minutes. That means that the light from the sun that is hitting your eyeball is over 8 minutes old.
At the end of September, scientists from NASA, using data from the Hubble Space Telescope announced that they had discovered water vapour plumes on Jupiter’s moon, Europa. The plumes extend more than 100 miles into space. The discovery was announced in a hastily arranged press conference amidst excitable rumours that NASA had discovered aliens. No aliens were forthcoming, but the discovery is certainly is good news for planetary scientists looking for extraterrestrial life.