https://en.wikipedia.org/wiki/Deep_S...te_Observatory

"Deep Space Climate Observatory (DSCOVR) (formerly known as Triana, unofficially known as GoreSat[3]) is a NOAA Earth observation and space weather satellite launched by SpaceX on a Falcon 9 launch vehicle on February 11, 2015 from Cape Canaveral.[4]

It was originally developed as a NASA satellite proposed in 1998 by then-Vice President Al Gore for the purpose of Earth observation. It is at the Sun-Earth L1 Lagrangian point, 1,500,000 km (930,000 mi) from Earth, to monitor variable solar wind condition, provide early warning of approaching coronal mass ejections and observe phenomena on Earth including changes in ozone, aerosols, dust and volcanic ash, cloud height, vegetation cover and climate. At this location it will have a continuous view of the Sun and the sunlit side of the Earth. The satellite is orbiting the Sun-Earth L1 point in a six-month period, with a spacecraft-Earth-Sun angle varying from 4 to 15 degrees.[5][6] It will take full-Earth pictures about every two hours and be able to process them faster than other Earth observation satellites.[7]

DSCOVR arrived at L1 by June 8, 2015, just over 100 days after launch.[8]"

For more reference on orbit see https://en.wikipedia.org/wiki/Lagrangian_point


The most recent image of our planet from L1 point 1.6 mil km away selected at a point in time the Americas are visible. The satellite always sees the day part of earth.




This is why;

Why is deep space so called? What's deep about it?

I guess its the space outside the earth's neighborhood (magnetic field etc) where you can observe earth from the "outside" of the system so to speak (even further out than moon?). So its the interplanetary space and beyond. It might be defined by the influence the planet's presence has. It has to qualify as "outside" (hence deep as opposed to near space?) in all aspects other than gravitational attraction (that is still significant even at L1 and a key reason behind such Lagrangian points to begin with).

Not a damn thing. It just sounds cool and far away so people use it to make whatever they are discussing seem important (and to get funding). Any random cubic meter of space is no more deep or interesting than Miley Cyrus' left nipple.

Bollocks! The farther you are from your typical, ordinary environment, the deeper you are. Deep in the ocean. Deep in liquid hot magma. Deep in outer space. You can also be deep in a book, deep in a dream, balls deep in some trouble.

Well there is a difference for sure between the space outside exosphere (500km to outer limits anywhere from say 10000km to 200000km say where most satellites are ) and inside down to the thermosphere (80k to 500km) (that eg space shuttle or the space station are orbiting in low earth orbits). There are still particles from earth's atmosphere that can be found on exosphere that do not exist in these numbers further out where you have the solar wind dominating typically outside our magnetic field.

https://en.wikipedia.org/wiki/Exosphere

The official entry to space is around 100km, the Karman line. But you do still have significant atmospheric effects at that level (reentry effects for spaceships appear a bit higher even)

https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line

See also this regarding exosphere;

Upper boundary

In principle, the exosphere covers distances where particles are still gravitationally bound to Earth, i.e. particles still have ballistic orbits that will take them back towards Earth. The upper boundary of the exosphere can be defined as the distance at which the influence of solar radiation pressure on atomic hydrogen exceeds that of Earth's gravitational pull. This happens at half the distance to the Moon (190,000 kilometres (120,000 mi)). The exosphere, observable from space as the geocorona, is seen to extend to at least 10,000 kilometres (6,200 mi) from Earth's surface. The exosphere is a transitional zone between Earth's atmosphere and interplanetary space.

As you see there is indeed a difference between what they refer as interplanetary space/deep space and the space in the neighborhood of earth.

For reference the LHC CERN vacuum where protons and circulating has 10^-10 torr pressure (1 atm is 760 torr) that corresponds to say 3 mil particles per cm^3 and is even better vacuum than what is found up to say 1000km above earth. Think about it! 3 mil particles per cm^3 is still significant vs what you have in interplanetary space where the solar wind provides about only 5-10 protons per cm^3 for comparison. Interstellar space is even less at about 1 proton per cm^3. I think the intergalactic space is approaching the critical density of the universe at about 5 protons per m^3. Imagine how small that is. (plus its all matter/energy density equivalent really ie standard baryonic plus dark matter and dark energy lol).

In our atmosphere right now hitting our face we have about 8 *10^26 molecules per m^3 and in protons equivalent (protons plus neutrons call it 2x protons) 2.3*10^28 protons/neutrons/m^3.

And yet we see it as empty space in daily life not thinking too much of it.

Same can be said for deep sh*t. The reason the fungus that produces magic mushrooms prospers deep inside sh*t is because the CO2 levels are higher, it is warmer, and there is no light. Once the fungus grows its way to the surface, the decrease in CO2 levels along with the light trigger the mushroom pinheads to sprout, eventually growing into caps that release it's spores to propagate.

Deep Space Nine was a cool show.

And the Deep Space Climate Observatory is worth every Florin we spent on it. I'm all for it and we need more of this type of endeavor.