A lunar tetrad – four total lunar eclipses in a row – began a year ago. The next eclipse in this tetrad will take place on April 4, 2015.
A pulsar is a rapidly spinning neutron star which is the small, incredibly dense remnant of much more massive star. How dense? A teaspoon of matter from a neutron star weighs as much as Mount Everest.
Proponents of solar power know that only a tiny fraction of the sun’s total energy strikes the Earth. What if we, as a civilization, could collect all of the sun’s energy? If so, we would use some form of Dyson sphere, sometimes referred to as a Dyson shell or megastructure.
Twice a year – on the March and September equinoxes – everyone worldwide supposedly receives 12 hours of day and 12 hours of night. Yet, in actuality, there is more daylight than nighttime on the day of the equinox. In fact, at mid-temperate latitudes, there is an additional 8 or so minutes of daylight on the day of the equinox. Why? There are two reasons why we have more than 12 hours of daylight on the day of the the equinox.
A Friday FAQ specially selected for equinox day.
Many believe Earth’s changing distance from the sun causes the change in the seasons. But that is not the case.
According to the definition of supermoon coined by Richard Nolle 30 years ago, the year 2015 has a total of six supermoons. They are the new moons of January, February and March and the full moons of August, September and October. The September 28, 2015 full moon will be the closest supermoon of 2015. The next supermoon – on March 20, 2015 – will cause a total eclipse of the sun! Follow the links inside to learn about the supermoons of 2015.
If you have heard of the Ides of March, you know you’re supposed to beware them. Why? In ancient Rome, the ides of March were equivalent to our March 15th. You probably know of the Ides of March thanks to William Shakespeare. In his play Julius Caesar, a soothsayer – or fortune teller – says to Caesar: Beware the Ides of March.
What are star trails? They are the continuous paths created by stars, produced during long time exposure photographs, as shown on this page. In other words, the camera doesn’t track along with the stars’ apparent motion as night passes (actually caused by Earth’s spin under the sky). Instead, the camera stays fixed, while, as the hours pass, the stars move. The resulting photos show the nightly movement of stars on the sky’s dome.
There’s a total solar eclipse coming up at this month’s equinox. When is the next one after this, and how often do we get an equinox-eclipse?
Your Friday FAQ! Here’s what causes those rings of light around the sun or moon … plus lots of cool photos.