“What lies west of Westeros?” Arya stark
ventured out into the wild sea to find out. For millions of years, humans have been exploring.
And as they pushed out further and further, they began exchanging knowledge of the places
they’d been to, expanding the boundaries of the world as we knew it. Our world map
was finally complete in the 1820s, with the discovery of Antarctica. But why stop at the
end of the earth? Or the moon? What’s the farthest we could go? Well, let’s find out….
Despite all our advancements, for a very long time, the farthest man could travel was restricted
to distances on the earth. In April of 1961, that all changed when humanity became a spacefaring
species. The Russian cosmonaut, Yuri Gagarin, was the first man in space. He blasted into
orbit on a 108-minute flight high above Earth. The Americans followed a few months later.
In 1969, the Apollo 11 mission landed the first two men on the Moon. No other statement
could have truly represented the significance of this event than that of Commander Neil
Armstrong, who described it as “one small step for man, one giant leap for mankind.”
Another great feat was achieved the next year in April 1970, when the crew of NASA's Apollo
13 swung wide around the far side of the moon at an altitude of 158 miles, putting them
248,655 miles away from Earth. It's the farthest our species has ever been from our home planet,
but it’s certainly not the farthest that we know about.
In fact, it’s mankind’s insatiable quest to know things far beyond what we can see
with our naked eyes that’s led to so many scientific advancements. To look at the tiniest,
we developed microscopes, and to look out beyond our world, we designed powerful telescopes.
Thanks to these advancements, the edge of our map extended far beyond our solar system.
Yet, till the 1900s, we still thought that our Milky Way galaxy was the entire universe.
But, not ready to give up, humans kept exploring in the hope that maybe there’s something
beyond the Milky Way as well. At this point, astronomers noticed that some stars were dimmer
than others. “Why?” they asked themselves. “Were they dimmer because they were smaller,
or because they were farther away?” The answer came from an astronomer named Henrietta
Swan Leavitt. Leavitt had studied thousands of Variable stars; stars whose brightness,
as seen from the Earth, fluctuates. She found that if certain stars, known as Cepheid variables,
pulsate at the same rate, they have the same brightness. This discovery proved to be a
milestone in measuring the distance of stars and galaxies, since it provided a yardstick
to co-relate brightness to distance. Think of it this way: if two Cepheid variables are
pulsating at the same rate but one is dimmer than the other, it would mean that the dimmer
star is farther away from the brighter star. Since we already knew the actual distances
of some of these stars, scientists could now determine the distance to other stars simply
by comparing its known luminosity to its observed brightness.
Around this time, work was also going on to install the Hooker telescope at Mount Wilson
Observatory, California. This would be the world's largest telescope from 1917 to 1949.
Astronomer Edwin Hubble arrived at this observatory in 1919. Yes, you guessed it right…the Hubble
Space Telescope is named in his honor. Using the Hooker Telescope, Hubble identified Cepheid
variables in several galaxies, including the Andromeda Nebula and Triangulum. Using Mrs.
Leavitt’s findings, he calculated and found that these bright objects far away from the
Milky Way were, in fact, galaxies outside our own. Andromeda is, in fact, the farthest
object we can see with our naked eyes on a dark, clear night. Now we knew that the Milky
Way was not the boundary of the universe; the universe extended far beyond it. To look
that far out we now have telescopes in space, just like the Hubble Space Telescope. But
the Hubble Telescope is not the first space telescope. That credit goes to the Orbiting
Astronomical Observatory 2, rightly nicknamed the Stargazer. Using these telescopes, we’ve
seen stars and galaxies far away. The enormous blue star nicknamed Icarus is the farthest
individual star we’ve seen to date. Normally, it would’ve been too faint to view, even
with the largest and most powerful telescopes. But it appears that nature wanted us to have
a look at it. It was because of a quirk of nature that the star’s feeble glow got tremendously
amplified. Astronomers using NASA’s Hubble Space Telescope were, therefore, able to pinpoint
this star and set a new distance record. It’s so far away that its light took 9 billion
years to reach Earth. The farthest galaxy observed is named EGS-zs8-1.
The light from it took 13.1 billion years to reach us. This means that what we see of
this galaxy today is actually the galaxy 13.1 billion years ago, long before the earth or
even our Sun came into existence. As a matter of fact, the universe is thought to be about
13.8 billion years old, so galaxy EGS-zs8-1 is also one of the earliest galaxies to have
formed in the cosmos. According to researchers at Yale, there are probably galaxies that
are even farther away. Yet another fascinating aspect of the universe
is that its size is not fixed. Instead, it’s always expanding. And the farther an object
is from us, the faster it’s moving away from us. So, by the time light from a faraway
galaxy reaches us, it’s actually moved away. A galaxy like the EGS-zs8-1, (which really
needs a nickname or something shorter), when it emitted its light, was 13.8 billion light-years
away from us, and it has been constantly moving away since then. According to some complex
calculations, that galaxy is about 32 billion light-years away from us now, while the star,
Icarus, is 14.4 billion light-years away. At this time, the observable universe, meaning
the area that can be observed from Earth or its space-based telescopes, is 93 billion
light-years in diameter. The expanding universe theory also means that
there’s a point in the universe where things are moving away from us at a speed faster
than the speed of light; a point beyond which, given our current scientific knowledge and
technology, we can’t look into. This is a place from where light can never reach us.
This means no one really knows what lies farthest from us, or how big our universe really is.
Some say that the universe is edgeless, while others believe in a multiverse hypothesis.
To be honest, I don’t know which of these two is true or if any of these is true, and
scientists also can’t know for sure. But we’re still inquisitive, just like our seafaring
ancestors were. And if time has taught us anything, we can be sure that one day in the
future, we’ll look far beyond what we can see today.
Okay, now that we’ve talked a lot about huge astronomical distances, it would only
be normal for you to be wondering: what’s the farthest that any of the objects we keep
hurling into space have reached so far? Well, here’s the answer: The space probe Voyager
1, launched by NASA in September 1977, is the manmade object that has traveled the farthest
and is still continuing its journey. As of June 3, 2019, in a period of over 41 years,
it’s traveled a distance of 13.5 billion miles and receives routine commands to transmit
data to Earth. Apart from the various scientific equipment it carries to conduct its research
and communicate with Earth, the probe also carries a gold-plated audio-visual disc to
initiate communication with intelligent life forms from other planetary systems; or to
at least make them know that we exist. The disc carries photos of the Earth and its
lifeforms, a range of scientific information, spoken greetings from people such as the Secretary-General
of the United Nations and the President of the United States, and a medley, "Sounds of
Earth," that includes the sounds of whales, a baby crying, waves breaking on a shore,
and a collection of music. I sure hope they like Chuck Berry! Wait a minute -- who doesn’t
like Johnny B. Goode? Do you think intelligent life form exist in
the universe? Will they be able to find the probe and understand the content of the golden
disk? Let me know down in the comments! If you learned
something new today, then give this video a like and share it with a friend.
But – hey! – don’t go away many light-years just yet! We have over 2,000 cool videos for
you to check out. All you have to do is pick the left or right video, click on it, and
enjoy! Stay on the Bright Side of life!
