Answer by Award-Winning Scifi Author C Stuart Hardwick
“We” have. You presumably missed the memo.
The far side of the moon was first photographed by Luna 3 in 1959. The above is a recent image captured by NASA’s LRO.
If you are asking why we can only see the near side from Earth, that’s because the moon tidally locked. It used to spin faster than it orbits, but just as its gravity causes a tidal bulge in Earth, our gravity causes a bulge in the moon.
Tidal bulges are carried along by the rotation of the body in question, and so create a slight gravitational imbalance. Today, this imbalance is pushing the moon away as a rate of 3.5 cm per year and slowing Earth’s rotation by about a millisecond per century. In the past, that same process slowed the moon’s rotation until it’s rotational and orbital periods became the same.
Now the moon’s stuck with it’s tidal bulge facing us. Any perturbation that would tend to turn the moon with respect to Earth gets cancelled out by the pull of our gravity on the moon’s bulge, and nothing is ever likely to disturb it enough to break free.
Steve Morris is an amateur astronomer and took this picture of the Black Eye Galaxy from his home. This stuff is floating above our heads in plain view. You just need the right equipment to see it and you don’t need Hubble (all of the time).
I copied this from his Facebook post in the Astronomy for Fun group.
Now think about this. You see the stars above you at night. Did you know you can see not only our own Milky Way Galaxy, but other galaxies as well?
You don’t need to depend on NASA for everything. This stuff is right above your head. You just need the right equipment, knowledge and determination to capture pictures like this.
Canadian citizen scientist photographers spotted a fleeting type of aurora not seen before, dubbed “Steve,” and scientists have started working out what’s causing them.
By Ramin Skibba
While the northern and southern lights have dazzled watchers of the night sky for millennia, vigilant citizen scientist photographers found another type of aurora over the past few years: a short-lived shimmering purple ribbon of plasma. Their intriguing discovery drew the attention of space scientists, who have just begun to study them.
“Dedicated aurora chasers, especially from Alberta, Canada, were out in the middle of the night, looking north and taking beautiful photos. Then farther south they happened to see a faint narrow purple arc as well,” says Elizabeth MacDonald, a space physicist at NASA Goddard Space Flight Center in Greenbelt, Maryland. There’s different physics behind those purple aurora, she says.
MacDonald led a team who observed the aurora by sending one of the European Space Agency’s Swarm satellites through it. The results suggest they’re a manifestation of accelerated and heated charged particles coming from the sunthat interact with a particular part of the Earth’s magnetic field in the ionosphere. The team published their findings in Science Advances Wednesday.
The citizen scientists weren’t sure about what they’d seen, so they called the strange aurora structure “Steve.” The name caught on, and MacDonald and her team kept it, proposing the backronym Strong Thermal Emission Velocity Enhancement (STEVE). While scientists had known about lower-latitude currents of charged particles for decades, they had no idea that they could produce auroras visible to the eye. But now that people have smartphones and digital cameras more sensitive than what scientists had back then, they can pick out these rare aurora, which last only about an hour.