Observatory. The letter contained the precise mathematical prediction of a previously undiscovered

8th planet in the solar system. A few days later, within 1° of its predicted location,

Neptune was discovered. Le Verrier was able to predict its location and existence based

on the seemingly inconsistent orbit of Uranus. But something still didn't quite add up. Uranus

orbit still showed slight deviations from what was to be expected. This lead some to

speculate that there could be yet another planet beyond the orbit of Neptune. This potential

9th planet received the nickname Planet X. And in 1930 it was announced that it had been

found. But Pluto was not what we expected to find. It was so tiny. Both in terms of

mass and size. So tiny in fact that it could not account for the orbital irregularities

of Uranus. It wasn't Planet X. In 1989, the space probe Voyager 2 made a flyby of Neptune.

New calculations based on the information it collected revealed that the orbits of Uranus

and Neptune were just fine. It turns out that the perceived anomalies in Uranus orbit was

the result of not having sufficiently accurate measurements. There was no need for a Planet X

as everything checked out. In hindsight, the discovery of Pluto was completely accidental.

While a certain fascination for the allusive Planet X continues to persist, most astronomers

agree that its existence is unlikely. That is until just a few months ago when new evidence

came to light which yet again opens up the possibility of a 9th planet in the solar system.

And this time, the evidence is actually quite compelling. By studying multiple trans-Neptunian

objects, with extreme and atypical orbits, two scientists have found a strange pattern.

This pattern, or orbital clustering as they call it, has about a 1/15,000 chance of being

a coincidence. It's much more likely that a so far undiscovered planet, roughly the

size of Neptune, has gravitationally influenced these distant bodies, leaving this orbital

clustering in its wake. This potential Planet X would have such an extreme orbit that it

would take roughly 15,000 years for the planet to orbit the sun only once. To put that into

context, 1 year on this planet would see the release of a staggering two fresh installments

in the Half-Life franchise. Researchers estimate that, if they are correct, they could visually

confirm its existence within the next half-decade.

You see this tiny red dot. That's a planet. An exoplanet orbiting a star 97 light-years

away. And this is a star 129 light-years away with an entire family of at least 4 exoplanets.

These photos and others just like them are the best images of exoplanets captured to date.

The best image of a star, other than the Sun of course, is this photo of the star Altair which

is roughly 17 light years away. It rotates at such a high velocity that instead of being

spherical it's gained a flattened oval shape.

Before the International Space Station there was another space station between 1973-1979

called Skylab. Unlike the modular construction of the ISS, Skylab was constructed and launched

as a single completed unit. Much like the other space stations at the time. The interior

of Skylab was so enormous that there was actually a viable concern that astronauts could find

themselves stuck in the middle of the station with nothing to grab onto. They would simply

have to wait for minor air currents to push them towards a wall or request help from a

crew member. However they later found that they could just swim if they had to, pushing air with

their hands to create a very minor amount of thrust which allowed them to slowly move around.

Getting stuff into space using rockets is, as you've likely heard many times before,

incredibly inefficient. The amount of fuel and thrust you need depends on the mass of

the spacecraft. But the more fuel you take with you the more massive the spacecraft becomes

and thus you need even more fuel. But then the spacecraft gets heavier so you need more

fuel, thus adding more mass to the spacecraft and thus requiring even more fuel. In other

words, there's a limit to what rockets and chemistry can provide. It's pretty insane

when you first realize that when this Space Shuttle reaches a stable orbit, it's lost

more than 85% of it's mass because 85% of it's total mass was fuel. More fuel is needed

to get from the surface to orbit then to get from orbit to the surface of the Moon. It's

been estimated that if the Earth was 50% larger, we would not be able to venture into space

at all. Not using rockets anyway. I mean the reason NASA and the Soviet Union began using

rockets was to get to space first. It wasn't about long-term efficiency or sustainability.

It was all about winning this global contest of firsts. And rockets where great for that

purpose. But once we started thinking of going to Mars, establishing colonies on other bodies,

building giant space stations and the like, we ran into some problems. The ISS for example,

is possibly the most expensive single thing ever constructed at an estimated cost of

150 billion US dollars. Many other methods have been proposed of course. A space elevator,

spaceplane, nuclear pulse propulsion, mass drivers, launch loops, beam-powered technology,

skyhooks, a space tower, space gun, balloons, and the list goes on and on. Each and every

one has it's one unique set of advantages, disadvantages, and problems we may have yet

to solve. But it's kinda funny when you think about it because we've done some amazing things.

We've walked on the Moon. We've visited and landed on multiple planets, moons, and other

celestial objects. We've build a space station as large as a football field. And we can detect

other planets, orbiting other stars that have the potential to sustain alien life. Yet this.

This insignificant expanse of about 100 km or so

remains as one of the biggest obstacles to space exploration.

The Curiosity rover on Mars landed on the red planet on August 5, 2012. One of its many

objectives is to dig up and analyze the Martian soil. To do this an on board instrument, abbreviated

as SAM, will resonate at different frequencies so that the soil can

pass through various filters for analyzation. And it sounds like this.

Now to celebrate the rover's one year anniversary on the planet, scientists at NASA thought it

would be fun to use the very same instrument to play the "Happy Birthday" song.

Which got to be the saddest and most depressing celebration in history.

Given a certain pronunciation of a certain planed named Uranus, Uranus has been the butt

of a joke ever since it was first named. Even I can't resist at times.

Oh, and 63 Earths can fit inside Uranus.

Both pronunciations are correct by the way butt ass-tronomers and most of the scientific community

seems to prefer Uranus over Uranus. My personal preference is Urmom, butt it could've been much worse.

Consensus on the name for the planet was not reached until almost 70 years after it had

been discovered. Because the guy who discovered the planet wanted to name it "Georgium Sidus" which

means "The Star of George" in honor of King George III. In other words Uranus could've been named George.

Besides humans many other animals has ventured into space. Many of you have likely heard

of the dog Laika. She became the first dog to orbit the Earth back in 1957. However the

very first animal in space where fruit flies aboard a rocket launched in 1947. In 1949

the first monkey was sent into space and in 1950 the first mouse was sent into space.

By the late 1960s many other animals like hamsters, turtles, rabbits, cats, frogs, goldfish,

various insects, etc. had been launched into space as well. The results of these experiments

has been crucial to our understanding of both the short-term and long-term effects of living

in space. Not just for humans but for the animals themselves. For example, in 2008 researchers

found that cockroaches that had been conceived in space became faster and stronger than their

Earth-dwelling siblings. Many birds will never be able to survive in low-gravity environments

as they actually need gravity to swallow food. Humans don't, but when the US and the Soviet

Union first sent people into space, they had no idea if weightlessness could somehow impair

our ability to swallow. If that had been the case, the first human in space

could possibly have died from asphyxiation or starvation.

"That's one small step for man, one giant leap for mankind."

This quote by Neil Armstrong as he takes his first steps on the surface of the Moon is possibly the most

misquoted quote in recent history. According to Armstrong himself he didn't say "one small step for man"

but actually said "one small step for A man". Something the world, newspapers, and

listeners at home back in 1969 completely missed. And if you think about it, it

doesn't make much sense. He would basically be saying

"That's one small step for mankind, one giant leap for mankind". But there's no audible "A" in the recording.

Then again, there's a lot of noise which makes it difficult to hear exactly what is being said. Maybe he

thought he said "for a man" but accidentally fumbled his words or maybe it's simply obscured by the noise.

Given the fact that all the gas giants in our solar system has rings one would assume

that planetary rings are quite common in the universe. So far we've found over 2000 exoplanets,

but as far as we can tell, none of them have rings. Except one. And it's truly an exceptional exception.

It's called J1407b and was discovered in 2012. The rings around this planet have an estimated radius of

90,000,000 km. Saturn's rings are tiny in comparison with a radius of less than 500,000 km. If we replaced

Saturn with J1407b, its rings would be more prominent and brighter than the Moon in the night sky.

It's common knowledge at this point that the main driving force behind early space exploration

was the fierce competition between the two Cold War rivals, the Soviet Union and the

United States. In the mids of this looming fear of a global nuclear war, and with the

world as their audience, these two super powers wanted nothing more than to win. In 1962 US

president John F. Kennedy addressed the nation in a now famous speech.

The Soviet Union had already beaten the US in many significant milestones. The first satellite in space,

the first photo of the far side of the Moon, the first human in space, and the first flyby

of another planet. Putting a man on the Moon would surely gain the US a clear lead in this

escalating Space Race. And as we all know, in 1969, Kennedy's promise came true.

But on September 20, 1963, Kennedy made a very different speech.

He proposes that the US and the Soviet Union should join

forces in their efforts to reach the Moon. Initially the Soviet Premiere Nikita S. Khrushchev

rejected Kennedy's proposals. After all, this was at the height of the Cold War. Unsurprisingly,

any form of collaboration between these sword enemies would be met with strong opposition.

Many decades later it was revealed by Khrushchev's oldest son that his father had had second

thoughts. Khrushchev had supposedly changed his mind and was in early November

of 1963 ready to accept Kennedy's offer to convert the Apollo lunar program into a joint

project between the two super powers. He believed, just like Kennedy, that both countries could

benefit from a collaboration rather than a competition. The Soviet Union had far better

rocket technology than the US and the US had more advanced computers than the Soviet Union.

Not to speak of the economical benefits of a joint mission to the Moon.

On November 22, 1963, President John F. Kennedy is assassinated. Because Khrushchev doesn't trust

the new president, Lyndon B. Johnson, all plans for a joint mission to the Moon dies along with JFK.

The story is fascinating because it had the potential to change history forever. Not just in terms

of space exploration, but it would surely have improved US-Soviet relations. Just imagine how different

the world could have been if Astronauts and Cosmonauts had stood on the Moon together.