This is the Milky Way galaxy. Home to planet Earth. The Milky Way is part of a large group of
galaxies known as the Local Group consisting of more than 54 gravitationally bound members. Most of them are quite small with the exception
of Andromeda, the Milky Way, and Triangulum. A few billion years into the future, these
larger members will collide and eventually form a much larger galaxy nicknamed Milkdromeda.
I know, very original… Now, lets go much further into the future,
about 100 billion years from now. Imagine that somewhere within Milkdromeda,
a habitable planet gives rise to a civilization of intelligent beings much like ourselves. At some point they invent a
powerful new telescope which will allow them
to explore space beyond the galaxy. But as they peek trough the telescope, they
find nothing. Nothing but darkness and empty space. They come to understand that they exist within
a seemingly endless and almost informationless void. Milkdromeda would appear to be a bastion of
light in a sea of darkness. It may sound like science fiction but it’s
actually a very plausible future. As the age of the cosmos approach 100 billion,
the expansion of the universe will cause all other galaxies to vanish beyond the cosmic
light horizon. This means that light from other galaxies
will no longer be able to reach us. Put another way, galaxies will
be pushed outside of the observable universe and
can thus no longer be observed. Everything outside of the Milkdromeda galaxy
will be virtually erased from existence. Just like observers in other galaxies will
experience the exact same phenomenon. If you think about it, we are rather fortunate
to exist at a point in time when we have access to such an abundance of information. Sure, there are a lot of things about the
universe that we do not understand but at least there’s hope that, one day, we will. The distant future of 100,000,000,000 CE however,
would be so information-deprived that when they aim their equivalent of the Hubble telescope
towards a seemingly empty region of space, the returned image would also be empty. And even though many questions could still
be answered by studying other phenomena, like hypervelocity stars and cosmic microwave
background, so much of the universe would be out of reach
and, consequently, unknowable. Of course, the same is true today. We have no way of knowing what lies beyond
the observable universe. So just as we imagine our populated bubble
to be a reflection of what lies beyond, intelligent inhabitants of an
isolated Milkdromeda may do the same. On September 7th, 2016, Earth had a very close
call with an asteroid known as 2016 RB1. The asteroid was between
7-16 meters in diameter and flew past the Earth above the
South Pole at an altitude of 34,000 km. To give you an idea of how close that truly
is, many communications and weather satellites orbit the Earth at an altitude of 42,000 km. In other words, it was so close that it flew
in between the Earth and our satellites. But like most asteroids, 2016 RB1
also suck at this astronomical game of Darts and
missed the board entirely. But even if it had scored a Bullseye, the
damages would likely have been minor. As some of you might remember, back in 2013,
an asteroid struck the Earth above Russia and caused damages to various
buildings and windows. That asteroid/meteor was not only larger at
20 meters wide but also had a greater impact velocity. So 2016 RB1 would, at most, have cause minor
damages to buildings and windows. However, it is a bit disconcerting that the
asteroid was only detected 24 hours
prior to it’s closest approach. If a future asteroid or comet should pose
a threat to the Earth, the glow of the meteor itself may be our first and final warning. In 1997 the very first commercial was filmed
in space aboard the Russian space station Mir. A prominent advertisement agency filmed the
commercial for an Israeli diary company and features a cosmonaut aboard the station drinking
the company’s milk. In 2001, the American fast food chain Pizza
Hut sent a vacuum-sealed pizza to the astronauts and cosmonauts aboard the ISS
as a commercial stunt. However, something far more
interesting happened back in 1993. A company known as Space Marketing, Inc.
announced that they would launch a giant
billboard into low-Earth orbit. The 1 km² billboard would have been made out
of a lightweight polyester film and if it had been launched it would’ve appeared to
be as large and bright as the Moon. The project never progressed
due to concerns about space debris and an inability
to attract adequate funding. But more importantly, it was
faced by immense opposition from both the public and
the scientific community. Which is completely understandable as no one
wants to have their sunset or astronomical observations interrupted by a giant floating
Coca-Cola sign. See, the guy in this stock footage couldn’t
even handle the mere prospect. People where so opposed to
the project that a bill was later introduced to ban all
obtrusive advertising in space. And for some inexplicable reason. Someone even
took the legislation and made it into a flash game. But.. Why? US based companies has since been prohibited
by law from launching any giant billboards into space but, then again, the ESA, Russia, China,
or anyone else could still do so if they wanted to. This is the Crab Nebula. It’s a stellar remnant of a star that went
supernova in 1054 CE. Well, the star actually went supernova about
6,500 years before that but the light from the explosion reached the Earth in 1054 CE. We know this, in part, thanks to historical
records describing the observations of the event. Here’s a quote from an ancient Chinese text: “I humbly observe that a guest star has appeared; above the star there is a feeble yellow glimmer.” The term “guest star” was used to describe a star that
had suddenly appeared before disappearing again. Of course, we now know the light they observed
was that of a distant supernova. The explosion of the star, located 6,500 ly
away, was so bright that it remained visible for almost two years and even remained visible
during the day for the first month of its appearance. And this is not an isolated
incident as quite a few supernovae have been observed and recorded throughout history. The first supernova for which records exist
is believed to have occurred in 185 CE. Chinese astronomers of the time wrote: “A strange star appeared in the middle of Nan Mun, It was like a large bamboo mat.” “It displayed the five colors, both pleasing
and otherwise. It gradually lessened.” “In the 6th moon of the succeeding year it
disappeared.” The brightest supernova in recorded history
was observed in 1006 CE. Even though the explosion occurred 7,200 ly
away it was bright enough to cast noticeable shadows on the ground and even allowed people
to see in the dark of night. On June 4, 1974, NASA began construction of
the very first orbiter of the new Space Shuttle program. The orbiter carried the designation OV-101
but was later planned to be named Constitution. However, after NASA received hundreds of thousands
of letters from avid fans of the TV-show Star Trek requesting the Space Shuttle to be named
Enterprise, NASA officials decided to seek the President’s approval for the name-change. Declassified White House documents reveal
that President Gerald Ford approved the renaming of the Space Shuttle for this exact reason
and one of his advisors wrote: “It seems to me ‘Enterprise’ is an
excellent name for the space shuttle.” “It would be personally gratifying to several
million followers of the television show ‘Star Trek’,” “one of the most dedicated constituencies
in the country.” The term Space Shuttle was likely inspired
by Star Trek as well. Prior to the 1960s the title Integrated Launch
and Reentry Vehicle, or ILRV, was used to describe a vehicle for traveling between a
planet’s surface and space. However, soon after the Shuttlecraft was introduced
in Star Trek, NASA officials began using the term Space Shuttle to describe such a vehicle. In any case, in recognition of it’s fictional
namesake, both the original cast and creator of Star Trek where invited to attend the dedication
ceremony of Space Shuttle Enterprise. Inside the Eagle Nebula, some
7,000 ly from Earth, there’s a beautiful region known as the
Pillars of Creation. But some astronomers believe that the formation
has already been destroyed after a nearby star went supernova some 9,000 years ago. So the light from the supernova has already
reached the Earth but as the shock-wave is much slower than the speed of light it only reached
and destroyed the Pillars of Creation 6,000 years ago. And as the nebula is 7,000 ly away,
it will be another millennium until the light from the formations destruction
reaches the Earth. In November of 1969, the crew of Apollo 12
safely landed on the Moon and soon experienced what it was like to walk
around on the Lunar surface. As the two astronauts conducted their extravehicular
activities they followed the instructions printed on the flip book attached to the wrist
of the spacesuit. Take some measurements, set up equipment,
collect some rocks, Playboy magazine… Playboy magazine? This is actually what Pete Conrad and Alan
Bean saw on their first EVA on the Moon. They both explained in a 1994 interview that: “It was about two and a half hours into the EVA,
I flipped the page over and there she was.” “I hopped over to where Pete was and showed
him mine, and he showed me his.” They revealed that the photos had been added as a
joke by the backup crew without anyone’s knowledge. One of the models featured in the flip book is even
visible in a photo released by NASA to the public. In 1910, the Earth passed through the tail
of a comet known as Halley’s comet. As astronomers examined
the tail of the comet prior to the fly-by they detected
a poisonous gas, known as cyanogen. The gas posed no threat to the Earth as it
was far too rarefied but when they announced their discovery, the public could only focus
on one aspect. Quite a few people panicked and began to prepare
for the incoming attack. Some purchased gas masks
while others capitalized on the hysteria by selling so called
“comet pills” to the less informed. And in a few extreme cases, people actually
committed suicide as they believed the comet to be a sign of the end of the world. I even found an article of a
man who crucified himself. But on May 18th, Earth passed through the
tail of the comet and absolutely nothing happened. In August of 2016 astronomers discovered an
exoplanet orbiting Proxima Centuari. At a distance of 4.2 ly it is the closest
star to the sun which makes the planet, Proxima Centuari b, the
nearest exoplanet to the Earth. What’s even more exciting is that the planet
is within the stars habitable zone which could allow for liquid water on its surface. However, much, much more
information is needed for a proper evaluation of its
potential for both life and habitability. But it’s exciting nonetheless! If the planet should turn out to be habitable,
it could become a serious candidate for human colonization at some
point in the distant, distant future. Because, well, space and human lifespans go
together about as well as Valve and the number 3. However, a project known as Breakthrough Starshot
is aiming to send a fleet of tiny automated probes that will travel at 20% the speed of light and
thus reach Proxima Centuari in only 20 years time. A trip that would otherwise take tens of thousands
of years using conventional rockets. And once the probes reach their destination
it would only take 4 years before we start receiving a continuous stream of photos and
information. In 2009, NASA launched the Kepler spacecraft. Kepler was designed to monitor the luminosity
of hundreds of thousands of stars with the aim of finding Earth-like exoplanets. It works like this. Pick a star. Observe the star over a long period of time. If the brightness of the star dims, congratulations,
you’ve just found yourself an exoplanet. Over the course of it’s mission, Kepler found
thousands of planets using this method but it also found something strange. The luminosity of a star known as KIC 8462852
was observed to decrease by as much as 22%. As a comparison, a Jupiter-sized planet would
only have caused about a 1% decrease. What’s more is that the dimming of the star
could not have been caused by a spherical object such as a planet because the dimming
exhibited an irregular and asymmetrical pattern. This is what it normally looks like when a
planet transits a star. A short symmetrical dip that lasts for a few
hours at most. This is what some of the data from KIC 8462852
looks like. In March of 2011 there’s a gradual dimming
of the star that lasts for about a week before returning to normal in a matter of days. Its luminosity is decreased by up to 15%. Beginning in February 2013, theres a whole
complex of dips that last for over 3 months. The dips are extremely irregular and varied
with some lasting for a couple of days and others lasting more than a week. And at one point, the star’s luminosity decease
by a whole 22%. Multiple hypotheses have been proposed but none
can fully explain all aspects of the observed data. The leading hypothesis is that the star is
surrounded by a swarm of cold and dusty comets. Another idea is that the star is much younger
than previously thought and could thus be
surrounded by a protoplanetary disk. Then there’s the more extreme explanation. Aliens. The idea is that an alien mega-structure is
blocking the light from the star. It is highly unlikely but it’s still a possibility.
Which is exciting by itself. At least until they inevitably prove that it was just exciting, grey, dusty rocks in space.