The June solstice, which for most of the world will fall on June 21 this year, is the longest day in the northern hemisphere and the day when the Sun is at its highest in the midday sky (see note). The origin of the word solstice is from the Latin words sol, which means Sun, and sistere, to stand… Continue reading The June Solstice
Tag: Astronomy
Astronomy Items
Jun 30 2015 – Leap Second
On June 30 2015 an extra second will be inserted into the very end of the day. This extra second is called a leap second. Why do we need leap seconds? Although we take the average length of a day to be 24 hours, the mean solar day, or average "natural" day measured by the… Continue reading Jun 30 2015 – Leap Second
Ultimate Fate of the Universe.
This post, which is the latest in my series on cosmology, is about the ultimate fate of the Universe, a subject which has engaged scientists, philosophers and religious leaders for centuries. There are many possible endings to the Universe, but the outline I will present here, which is sometimes called "The Big Freeze", is the most commonly held… Continue reading Ultimate Fate of the Universe.
The Future of humanity
As described in my previous post (The Future of the Sun), in about 5 billion years time the Sun will swell up to at least 100 times its current diameter and this will make the surface of the Earth far too hot to sustain life. What Sunrise might look like when the Sun is a red… Continue reading The Future of humanity
The Future of the Sun
The Sun, central to our Solar System, generates energy through nuclear fusion, combining hydrogen into helium. Over billions of years, it will evolve into a red giant, ultimately shedding outer layers to form a planetary nebula and becoming a white dwarf. Life on Earth will become uninhabitable well before these changes occur.
Explaining Science 