If you were looking with the eye alone, how far away in space would our planet Earth still be visible?
Here is Earth from 900 million miles away, from the vantage point of the rings of Saturn. Image via the Cassini spacecraft, which has been orbiting Saturn since 2004.
This image was acquired by Cassini on July 19, 2013. How far away from Earth can we be, to see it still with our own eyes? To answer this question, you have to take into account how brightly Earth reflects sunlight. And the sun itself is an important factor. As seen from any great distance, Earth appears right next to the sun; from a great distance, the glare of our local star would make Earth difficult or impossible to see. But spacecraft exploring our solar system have given us marvelous views of Earth.
So imagine blasting off and being about 300 kilometers – about 200 miles – above Earth’s surface. That’s the height at which the International Space Station (ISS) orbits. The surface of the Earth looms large in the window of ISS. In the daytime, you can clearly see major landforms. At night, you see the lights of Earth’s cities.
Observers of Wednesday morning’s total lunar eclipse might be able to catch sight of an extremely rare cosmic sight.
On Oct. 8, Interested skywatchers should attempt to see the total eclipse of the moon and the rising sun simultaneously. The little-used name for this effect is called a “selenelion,” a phenomenon that celestial geometry says cannot happen.
And indeed, during a lunar eclipse, the sun and moon are exactly 180 degrees apart in the sky. In a perfect alignment like this (called a “syzygy”), such an observation would seem impossible. But thanks to Earth’s atmosphere, the images of both the sun and moon are apparently lifted above the horizon by atmospheric refraction. This allows people on Earth to see the sun for several extra minutes before it actually has risen and the moon for several extra minutes after it has actually set. [How to See the Total Lunar Eclipse (Visibility Maps)]
The Daily Prompt asked the question, on Valentine’s Day, “Remember your first crush? Think about that very first object of your affection.”
My first love — Space, the Final Frontier
Maybe it’s a strange love, but honestly, I’m a geek gal from way back. Fascinated by Mr. Spock on Star Trek when I was middle school, hanging out with a Boyscouting program viewing stars and programming computers in high school, is it too surprising that science and star made my heart beat faster?
So, when I thought about it, my first real crush/love was this building…or, more accurately…what lay inside.
The star projector.
I remember lingering behind once the crowds had filed out. Sometimes my family would have to come looking for me. Usually, I would be asking questions about how it worked from the projectionist or staff member. If I was really lucky, there would be guest speaker…a local weatherman or university astronomer…swoon!
Maybe I should’ve been one myself…but, my other love was computers. Need I say more?
The satellite ran out of fuel Oct. 21 and had been steadily losing altitude since, tugged by Earth\’s gravity.
The 1.2-ton GOCE satellite is small in comparison to other spacecraft that recently crashed back into the atmosphere.
In January 2012, Russia\’s failed 14-ton Phobos-Grunt Mars probe returned. In 2011, NASA\’s 6.5-ton Upper Atmosphere Research Satellite and Germany\’s 2.4-ton X-ray ROSAT telescope re-entered the atmosphere.
So this weekend started out on a bad note. Well, bad for my wallet at least, great fun for me!
I was looking around for a good low light lens for the upcoming Night Sky Photography workshop that my astronomy club is putting on September 7-8 (if you are in the area you too can participate…its $120 to learn from one of the masters of the craft Dennis Mammana).
So as I was perusing the Samy’s Camera store ads, I noticed that they were having a Photo Expo at the Pasadena Convention Center…Yeah!!
Right as you walked in to the Expo, there they were…my dream lenses! No, those aren’t telescopes (although they could be), they are just really long lenses. The Sigma above what their 400mm F2.8 monster. The Canon 400mm was surprisingly light for all the glass in the lens. Both were sharp edge to edge. However, I…
NASA’s Spitzer Space Telescope was launched 10 years ago and has since peeled back an infrared veil on the Cosmos. The mission has worked in parallel with NASA’s other “Great Observatories” (Hubble and Chandra) to provide coverage of the emissions from galaxies, interstellar dust, comet tails and the solar system’s planets. But some of the most striking imagery to come from the orbiting telescope has been that of nebulae. Supernova remnants, star-forming regions and planetary nebulae are some of the most iconic objects to be spotted by Spitzer. So, to celebrate a decade in space, here are Discovery News’ favorite Spitzer nebulae.
First up, the Helix Nebula — a so-called planetary nebula — located around 700 light-years from Earth. A planetary nebula is the remnants of the death throes of a red giant star — all that remains is a white dwarf star in the core, clouded by cometary dust.
The moon will block the sun Tuesday in a total solar eclipse, but only for spectators in parts of Australia and in the southern Pacific Ocean. For the rest of us, several webcasts will be available to remotely watch the celestial alignment of the sun and moon.
The only total solar eclipse of 2012 will begin Tuesday (Nov. 13) at 3:35 p.m. EST (2035 GMT), though it will be early Wednesday morning (Nov. 14) for observers watching the event in Australia.
The path of totality is about 108 miles (174 kilometers) wide and 9,000 miles (14,500 km) long, and covers a three-hour period. Much of the solar eclipse’s path is over the open Pacific Ocean, making it difficult to observe. [Video: Watch Path of Nov. 13-14 Total Solar Eclipse]