If you could see stars and planets from outer space, both would shine steadily. But – from Earth – stars twinkle while planets shine steadily. Why?
The first Blood Moon eclipse in a series of four is coming up on the night of April 14-15, 2014. This total eclipse of the moon will be visible from the Americas. We in astronomy had not heard the term Blood Moon used in quite this way before this year, but now the term is becoming widespread in the media.
Get ready to watch the total lunar eclipse on Monday night (April 14-15.) A total lunar eclipse is one of the most dramatic and beautiful – and easiest-to-view – of all astronomical events. During a total lunar eclipse, the sun, Earth and moon form a line in space. Earth’s shadow falls on the face of the moon. Click into this post to learn how to watch the eclipse.
Mars is the world orbiting the sun one step outward from Earth’s orbit. Earth takes one year to orbit the sun once. Mars takes about two years. The orbits of Earth and Mars are the reason Mars is one of the most fascinating planets to watch in our sky, and they are the reason Mars is sometimes bright and sometimes faint. On April 8, 2014, Earth goes between the sun and Mars. That’s why Mars is so bright this April.
The brightness of Mars in our sky depends on where our two planets are in orbit around the sun. Sometimes Earth is close to Mars, and sometimes we are far away.
We are relatively close – and Mars appears at its brightest in our sky for that two-year period – every time Earth passes between the sun and Mars. That’s what’s happening today.
Have a birthday this month? If yes … happy birthday! Your birthstone is the diamond, symbol of enduring love.
Diamonds’ cold, sparkling fire has held us spell-bound for centuries, inspiring rich, passionate myths of romance, intrigue, power, greed, and magic. Ancient Hindus, finding diamonds washed out of the ground after thunderstorms, believed they were created by bolts of lightning. Read more ….
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.
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.
Get up early and look for Venus in the predawn and dawn sky before sunrise. It’s bright! In fact, it’s the third-brightest celestial body to light up the heavens, after the sun and moon. Here’s why it’s so bright.
The Martian moons are tiny. The larger moon, Phobos, is only about about 14 miles across. And Deimos is about half that size. They orbit Mars more closely than our moon orbits Earth, but because they’re so tiny they appear smaller than our moon does.
In fact, Deimos, the more distant moon, looks like a star in Mars’ sky. But it’s twice as bright as any star-like object seen in Earth’s sky. Deimos orbits at nearly the same speed Mars rotates – so it needs three Martian days to crawl from one side of Mars’ sky to the other. And, by the way, a day on Mars is about the same length as Earth’s day.
On the other hand, Phobos – the larger and closer of the two moons – zooms around Mars two and a half times every Martian day. Because it out-races Mars’ rotation, Phobos rises in the west and sets in the east. Phobos appears about a third as large in the Martian sky as our moon does in Earth’s sky.