Post by pim on Aug 16, 2021 17:42:33 GMT 10
I love stargazing. I used to do a bit at the Mt Stromlo Observatory in Canberra before it was destroyed in the 2003 bushfires. In Broken Hill they have a place 10km outside the town in the hills of the Barrier Ranges where there’s no light pollution and they have the telescopes set up and pointed in the right direction. Not just “up” but at the planets that are visible at that time of year. I got to see the planet Neptune. The desert sky at night is truly a magnificent sight and you get a Southern Hemisphere view of the Milky Way in all its splendour which alone makes a weekend in Broken Hill worth it. It’s easily reachable from Adelaide at 450km on a very good road.
What Does Earth Look Like From Outer Space?
earthsky.org/astronomy-essentials/in-space-how-far-away-can-you-see-earth/
Venus, Earth, and Mars on November 18, 2020, as seen via the NASA-ESA Solar Orbiter (SolO). This image was captured from about 155.7 million miles (250.6 million km) away. That’s in contrast to our sun’s distance from Earth of about 93 million miles (150 million km). In this image, the sun is located on the right, outside the image frame. Image via ESA/ NASA/ NRL/ Solar Orbiter/ SolOHI.
What does Earth look like from outer space? And … how far away from Earth can we be and see it still with our own eyes?
To find the answer to these questions, let’s take an imaginary trip through the solar system. Spacecraft exploring our solar system have given us marvelous views of Earth. Keep reading, and check out the photos on this page, to see how Earth looks from various other places in our own neighborhood of space.
First, imagine blasting off and being about 200 miles (300 km) above Earth’s surface. That’s about the height of the orbit of the International Space Station (ISS). From the window of the ISS, the surface of the Earth looms large. In the daytime, you can clearly see major landforms. At night, from Earth orbit, you see the lights of Earth’s cities.
Earth in daylight, from the International Space Station in 2012. The North American Great Lakes shine in the sun.
Earth at night, from the ISS in 2012. Ireland is in the foreground, and the United Kingdom in the back and to the right. A bright sunrise is in the background. Greens and purples show an aurora borealis along the rest of the horizon.
Let’s get farther away, say, the distance of the orbit of the moon.
As we pass the moon – some quarter million miles (about 380,000 km) away – Earth looks like a bright ball in space. It’s not terribly different from the way the moon looks to us.
The first images of the Earth from the moon came from the Apollo mission. Apollo 8 in 1968 was the first human spaceflight to leave Earth orbit. It was the first earthly spacecraft to be captured by and escape from the gravitational field of another celestial body, in this case the moon.
It was the first voyage in which humans visited another world and returned to return to Earth.
Earthrise Apollo 8 1968
In the decades since Voyager first began traveling outward, moon exploration has become more common. The robotic Kaguya spacecraft orbited around Earth’s moon in 2007. Launched by Japan, and officially named the Selenological and Engineering Explorer (SELENE), Kaguya studied the origin and evolution of the moon. The frame below is from Kaguya’s onboard HDTV camera.
Earth viewed from the moon by Kaguya in 2007.
Another image from Kaguya, which got footage and stills of Earth setting. Remember that, if you were on the moon, you would not see Earth rise or set. But spacecraft in orbit around the moon do experience this scene.
Now let’s keep moving outward until we can see both the Earth and moon together in space. The next picture was mind-blowing when first released. It shows a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977.
This picture of a crescent-shaped Earth and moon – 1st of its kind ever taken by a spacecraft – was recorded September 18, 1977, by Voyager 1 at a distance of 7.25 million miles (11.66 million km) from Earth. The moon is at the top of the picture and beyond the Earth as viewed by Voyager.
Since 1977, many robot spacecraft have ventured outward into our solar system. The mosaic below shows images of Earth and the moon acquired by the multispectral imager on the Near Earth Asteroid Rendezvous Spacecraft (NEAR) on January 23, 1998, 19 hours after the spacecraft swung by Earth on its way to the asteroid 433 Eros. The images of both were taken from a range of 250,000 miles (400,000 km), approximately the same as the distance between the two bodies.
Speeding outward from the Earth and moon system, you pass the orbits of the planets Mars, Jupiter and Saturn. From all of these worlds, Earth looks like a star, which gets fainter as you get farther away.
Earth and moon, as seen from Mars by NASA’s Curiosity rover on January 31, 2014.
Earth seen behind the rings of Saturn. See us in the lower right? Mars and Venus are in the upper left. Image via the Cassini spacecraft, July 19, 2013.
This is the famous image known as Pale Blue Dot. It’s a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles). Earth is the bluish-white speck approximately halfway down the brown band to the right.
... there’s more
earthsky.org/astronomy-essentials/in-space-how-far-away-can-you-see-earth/
Venus, Earth, and Mars on November 18, 2020, as seen via the NASA-ESA Solar Orbiter (SolO). This image was captured from about 155.7 million miles (250.6 million km) away. That’s in contrast to our sun’s distance from Earth of about 93 million miles (150 million km). In this image, the sun is located on the right, outside the image frame. Image via ESA/ NASA/ NRL/ Solar Orbiter/ SolOHI.
What does Earth look like from outer space? And … how far away from Earth can we be and see it still with our own eyes?
To find the answer to these questions, let’s take an imaginary trip through the solar system. Spacecraft exploring our solar system have given us marvelous views of Earth. Keep reading, and check out the photos on this page, to see how Earth looks from various other places in our own neighborhood of space.
First, imagine blasting off and being about 200 miles (300 km) above Earth’s surface. That’s about the height of the orbit of the International Space Station (ISS). From the window of the ISS, the surface of the Earth looms large. In the daytime, you can clearly see major landforms. At night, from Earth orbit, you see the lights of Earth’s cities.
Earth in daylight, from the International Space Station in 2012. The North American Great Lakes shine in the sun.
Earth at night, from the ISS in 2012. Ireland is in the foreground, and the United Kingdom in the back and to the right. A bright sunrise is in the background. Greens and purples show an aurora borealis along the rest of the horizon.
Let’s get farther away, say, the distance of the orbit of the moon.
As we pass the moon – some quarter million miles (about 380,000 km) away – Earth looks like a bright ball in space. It’s not terribly different from the way the moon looks to us.
The first images of the Earth from the moon came from the Apollo mission. Apollo 8 in 1968 was the first human spaceflight to leave Earth orbit. It was the first earthly spacecraft to be captured by and escape from the gravitational field of another celestial body, in this case the moon.
It was the first voyage in which humans visited another world and returned to return to Earth.
Earthrise Apollo 8 1968
In the decades since Voyager first began traveling outward, moon exploration has become more common. The robotic Kaguya spacecraft orbited around Earth’s moon in 2007. Launched by Japan, and officially named the Selenological and Engineering Explorer (SELENE), Kaguya studied the origin and evolution of the moon. The frame below is from Kaguya’s onboard HDTV camera.
Earth viewed from the moon by Kaguya in 2007.
Another image from Kaguya, which got footage and stills of Earth setting. Remember that, if you were on the moon, you would not see Earth rise or set. But spacecraft in orbit around the moon do experience this scene.
Now let’s keep moving outward until we can see both the Earth and moon together in space. The next picture was mind-blowing when first released. It shows a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977.
This picture of a crescent-shaped Earth and moon – 1st of its kind ever taken by a spacecraft – was recorded September 18, 1977, by Voyager 1 at a distance of 7.25 million miles (11.66 million km) from Earth. The moon is at the top of the picture and beyond the Earth as viewed by Voyager.
Since 1977, many robot spacecraft have ventured outward into our solar system. The mosaic below shows images of Earth and the moon acquired by the multispectral imager on the Near Earth Asteroid Rendezvous Spacecraft (NEAR) on January 23, 1998, 19 hours after the spacecraft swung by Earth on its way to the asteroid 433 Eros. The images of both were taken from a range of 250,000 miles (400,000 km), approximately the same as the distance between the two bodies.
Speeding outward from the Earth and moon system, you pass the orbits of the planets Mars, Jupiter and Saturn. From all of these worlds, Earth looks like a star, which gets fainter as you get farther away.
Earth and moon, as seen from Mars by NASA’s Curiosity rover on January 31, 2014.
Earth seen behind the rings of Saturn. See us in the lower right? Mars and Venus are in the upper left. Image via the Cassini spacecraft, July 19, 2013.
This is the famous image known as Pale Blue Dot. It’s a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles). Earth is the bluish-white speck approximately halfway down the brown band to the right.
... there’s more