A supernova is a stellar explosion – destructive on a scale almost beyond human imagining. If our sun exploded as a supernova, the resulting shock wave probably wouldn’t destroy the Earth, but it would remove all life from Earth’s surface. Also, the sudden decrease in the sun’s mass would probably free the Earth to wander off into space.
Radiocarbon dating is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past. It can be used on objects as old as about 62,000 years. Follow the links inside to learn more about radiocarbon dating.
As seen from the Northern Hemisphere, the stars seem brighter in winter. Here’s why …
The planets in our solar system orbit around the sun. One orbit of the Earth takes one year. Meanwhile, our sun and its family of planets orbit the center of our Milky Way galaxy. In 90 seconds, we move some 20,000 kilometers – or 12,500 miles – in orbit around the galaxy’s center. Our Milky Way galaxy is a big place. Even at this blazing speed, it takes the sun approximately 200 million years to complete one journey around the galaxy’s center. This amount of time – the time it takes us to orbit the center of the galaxy – is sometimes called a “cosmic year.”
Those who live at or visit high northern latitudes might at times experience colored lights shimmering across the night sky. This ethereal display is known as the aurora borealis, or northern lights. What causes these lights to appear?
The shape of snowflakes is influenced by the temperature and humidity of the atmosphere.
The December solstice occurs just a few weeks before Earth reaches its perihelion – the point in our world’s orbit in which we are closest to the sun – each year. December solstice always comes around December 21. Perihelion comes in early January. At perihelion in January, Earth is about 147 million kilometers from the sun, in contrast to about 152 million kilometers in July.
The Age of Aquarius is an astrological age, which shifts roughly every 2,150 years. It’s defined by the sun’s position at the time of the March, or vernal, equinox. The Age of Aquarius begins when the March equinox point moves out of the constellation Pisces and into the constellation Aquarius. But there’s no definitive answer as to when that will be. This post explores some of the possibilities.
UPDATED JAN. 2, 2014. For those at high latitudes, this year has gotten off to a spectacular start, with many beautiful auroras seen already. Space weather forecasters at NOAA are now estimating a 40% chance of polar geomagnetic storms tonight (January 2, 2014) as the solar wind continues to blow and buffet Earth’s magnetic field.
Just like you or me, Earth casts a shadow. Earth’s shadow extends millions of miles into space, in the direction opposite the sun. There are several good times to think about and be aware of Earth’s shadow.