On the 18th of September, 1846, French mathematician
Urbain Le Verrier sent a letter to the Berlin 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.
