• Earth’s first artificial satellite
• Marked the start of the Space Race
• Sputnik #1 launched in 1957 by the Soviet Union
• Sputnik #2 held Laika
• Sputnik #3 held instruments to bring back Space Data, but they failed

• First a radio broadcast on BBC in the 1970s, later books comics, shows, movies, etc
• Created by Douglas Adams, who was not actually a scientist
• Exposed an entire generation of kids to space, around the same time as Carl Sagan

• The Voyager Mission has two spacecraft, both launched in 1977
• Each contain a copy of the “Golden Record”, a literal record that can be placed on a record player, including music, culture, etc, for intelligent life to see what Earth was like
• They are now 15 billion miles away from Earth (160 times as far as the sun)

• Debris left by comets and asteroids
• Created by friction between meteors and air particles and the subsequent vapor
• Some reoccur, like the Perseids Shower in August
• Usually named after stars or constellations

Note: this is also cheating, I’m explaining Time Retrograde not exactly retrogression, but bear with me.

• “Retrograde” is when a planet seems to move backward, retracing its orbit
• No bodies in our solar system actually change direction; retrograde is only our perception of a planet’s movement from earth due to our differing speeds of orbit
• The planets that do this most often are Mercury (which will be entering retrograde in July of 2025) and Venus

• Shows the phases of a relationship: Collision, Growth, End
• Collison Theory = only some collisions result in reaction
• Growth Theory = the universe is constantly expanding and growing
• End Theory = how will the universe end? Heat death, reversal to a  singularity, or being torn apart?

• A three part series about mental health, contrasted with high-minded scientific concepts
• Gravity = universal force of attraction acting between all bodies of mater
• Entropy = disorder or lack of predictability in a “system”
• Negentropy = the reverse of entropy

• The explosive death of an enormous star, so enormous and colorful it can be seen millions of light years away with the naked eye
• Can form a black hole when the star is 25 X as large as our Sun
• Betelgeuse, a red supergiant in our solar system, is expected to “go supernova” sometime in the next few hundred years, though it’s unlikely to happen in our lifetimes

• Is there or is there not intelligent life out there?
• Scientists are divided, both over if intelligent life exists and what counts as intelligent life: does it have to be humanoid or just have a brain, does it have to breathe air, etc.
• Fermi’s Paradox: “if the universe is so big, there must be something out there, but if they are, why haven’t they found us?”