Blog 8 – Life on Enceladus?

Several Jovian moons are candidates for extraterrestrial life.  One of these is Enceladus, a medium-sized moon of Saturn.  Like Europa, there is strong evidence for a subsurface ocean, which is likely 30-40 kilometers below the moon’s surface, and then extends down another 30 kilometers.  Due to the suspected ocean’s thickness, it is more likely that there is a habitable zone.  A very recent discovery about Enceladus is about its bursts of matter that skyrocket off the surface like the geysers in Yellowstone.  It was recently discovered that these fountains contain ice, or water.  Because of this it may be simpler to discover life on the planet because a spacecraft could fly through a blast of ice and determine if the spray has any life.  The discovery is also a reminder that the universe is full of surprises.

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Ice Fountains on Enceladus


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Blog 7 – Interplanetary Life Travel

From the title, you might think the subject of this blog is about human space travel, something that isn’t very developed today.  However, it is possible that some life forms before us have experienced travel between the planets.  There are theories that support the idea that life originated on either Venus or Mars, and then spread to the Earth.  This is possible because, very early on in the Solar System, there was much more bombardment of rocks among the planets, amounting to several tons of material.  It is difficult to believe that life can survive a trip through space, but we already know that meteorites and comets can harbor organic life.  Also, some extremophiles, such as tardigrades, have been proven to be able to survive at least some amount of time in space.  It is an interesting thought, that life as we know it was implanted from one of our neighbors or potentially even more distant places.

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A Tardigrade


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Blog 8: What If You Fell In A Blackhole?

In a black hole, spacetime is curved infinitely. Light cannot escape. Black holes have fascinated mankind for years, but what would happen if you actually reached the event horizon?

What would happen if you fell into a black hole?

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It’s likely you would be pulverized by other objects, burn via light radiation, experience spaghettification, or be magnetically ripped apart due to the magnetic fields inside. It won’t be pretty.

If you do intend on visiting a black hole, Charles Liu, an astrophysicist who works at the American Museum of Natural History’s Hayden Planetarium, suggests going big or going home.

“If you had a black hole the size of our solar system, then the tidal forces at the event horizon … are not quite that strong. So you could actually maintain your structural integrity,” Liu said.

 

Source: http://www.livescience.com/19683-happen-fall-black-hole.html


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Blog 7: Wait But Why

Where is everybody?

That is essentially the question asked in the Fermi Paradox.

Compared to Earth and our solar system, the universe is extremely vast and extremely old. Surely there must be intelligent life somewhere within the depths of the unexplored universe?

The Drake Equation (written as N = R* • fp • ne • fl • fi • fc • L) attempts to determine a plausible number of civilizations and some estimates can be around 10,000 or more. So where are all the aliens?

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Source: http://www.space.com/25325-fermi-paradox.html


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Alien Life Closer to Home

Although intelligent life has yet to make its debut for us, extraterrestrial life may be a little closer that we typically think of- specifically Martian life.  No, no, not little green men or facehugger kind of Martian life, but microbial life.  And not just on Mars either!  The three likeliest candidates for elementary life in our solar system are the places where it is likely there is or was liquid water.

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Martian polar ice cap: msss.com

We know there is ice on Mars, and it’s not entirely unlikely that liquid water exists, in some capacity, somewhere on the planet.  That makes it prime real estate for young life.  There is also evidence for sub-surface liquid water on both Europa and Enceladus, making a wonderful, contained environment for life to grow.  There is also a possibility that life of a different kind than we’re used to could inhabit the liquid methane/ethane lakes on Jupiter’s moon, Titan.  All of these are exciting possibilities for the observation of life in its youngest stages.

Source: wikipedia


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Upcoming Solar Eclipse

As some of you may know, there is an upcoming Total Solar Eclipse that will be visible in Nashville, TN! The last total solar eclipse visible from the United States was back in 1998, so it’s been a while, but it’s finally back! On August 21st, the eclipse will be visible at 1:27 PM local (Nashville) time and will last for almost 2 minutes. So prepare your eclipse glasses (this is very important for the safety of your eyes!) and remember to take some time to watch this amazing sight that won’t be visible in the United States again until April 8, 2024. Another tip: if you want your family to come as well, make sure you have hotel rooms booked; they are filling up! I know I booked a room for my family already 🙂

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A map of the eclipse route

So how does a solar eclipse actually happen? Well, since the moon orbits the Earth while the Earth orbits the sun, sometimes the moon gets in between the sun and the Earth, and while we’re under the shadow of the moon, the sun will appear blacked out— this is known as a solar eclipse. Not all eclipses are total, sometimes only a portion of the sun is blocked rather than the entirety, which is why the one on August 21st is so special. Go watch it, I promise you, you will be amazed.


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Black Holes

While the concept of black holes has become a cultural phenomenon thanks to movies such as Interstellar, it still seems like the general public knows very little about them. In order to help clarify any misunderstandings, welcome to a brief introduction on black holes. In essence, a black hole consists of a massive amount of mass jam-packed into a tiny volume. In order to get a better understanding of this, NASA offers a simple example: for a start 10 times the mass of our sun, it would have all of its mass packed inside of a sphere the diameter of New York City in order to create a black hole. This unbelievably large density is able to prevent anything, even light, from escaping its radius. But how does this work?

Escape Velocity
Escape Velocity

The answer is simple physics. Take the equation given above for the escape velocity of an object attempting to escape the gravitational pull of another object. As you can see, there is no bound to the escape velocity. Therefore, when the mass is large enough and the radius is small enough, the escape velocity can surpass the speed of light. Since nothing is faster than the speed of light, nothing will be able to escape within the given radius. And that is a short tutorial on the functionality of black holes.

Sources: Black Holes and Escape Velocity


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The Fermi Paradox

“Where are they?” asked Enrico Fermi to his colleagues in 1950.  Where is all the life that, by all rights, should populate our galaxy and the rest of the universe?  The Fermi Paradox arises from the knowledge that the whole of human history is but a blip in the cosmic calendar.  If we have so quickly evolved and nearly made it to the reality of interstellar travel, then it stands to reason that the universe and our galaxy should be teeming with life.  According to Fermi’s math, the galaxy should have produced countless versions of intelligent life, some existing long before our own, and that logically Earth should have been visited repeatedly by extraterrestrials by now.

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Enrico Fermi: image from wikipedia

So where could they be if life should be so common?  Perhaps life as we know it is far less common than we believe- maybe the Earth and its inhabitants are extremely unique in our universe.  Maybe civilizations are too far apart in both space and time for us to ever make contact outside of our solar system.  Or perhaps life is out there, but its essence is so foreign to us that we wouldn’t even know if we found it.  There is another, slightly scarier, option though.  Perhaps life- even intelligent life- is quite common among the stars.  And maybe what keeps them from populating the galaxy is some catastrophic event that very few, or none, survive.  We’d never know until it happened to us.  But it’s nothing that we can really worry about.  All we can do is keep on keeping on down on Earth and exploring our sky to find out the facts.

Source: wikipedia


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The Comet Time Forgot… Until Now

A stone carving at a major archaeological site suggests a comet struck Earth thousands of years ago and started an ice age.

Göbekli Tepe is an archaeological site located in modern-day Turkey.  Built before Stonehenge, it served as an ancient temple site and religious center where multiple people would gather, but it also seemed to have been an astronomy observatory.   Archaeologists have studied several stone carvings at Göbekli Tepe.  The Vulture Stone, however, depicts a major astronomical event that changed human history.

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Replica of the Vulture Stone at Göbekli Tepe

The Vulture Stone depicts an ancient comet impact.  Archaeologists found the vultures and animals featured on the pillar correspond with ancient constellations and the comet.  They traced the positions of the constellations to around 10,950 BC, nearly 13,000 years ago.  This is also the date when a mini ice age called the Younger Dryas began.  The comet impact could have caused this ice age.

What happened was that the comet’s nucleus broke apart and struck the Earth.  The carving of a man with a missing head might indicate a significant loss of human life.  The ice age that followed led to the rise of agriculture.  The barley, wheat, and animals that hunter-gatherers relied on were in short supply during the Younger Dryas.  Humans had to resort to settling down, growing their own vegetables and fruits, and raising livestock.  The Younger Dryas herald a new age in human development, one where agriculture led to rise of villages, cities, and civilizations.  And it all could be attributed to this one comet impact.

 

Sources: Ancient stone carvings confirm how comet struck Earth in 10,950BC, sparking the rise of civilisations

Ancient Stone Carvings Show a Comet Swarm Hitting Earth Around 10,950 BCE

 

 

 


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Drake Equation

You may have heard of the Drake equation before, and you may have heard that it can “predict” the number of aliens we may one day face (or fight?). Well, you’re not too far off. The Drake equation allows astronomers and scientists to estimate the number of civilizations that exist in the deep vast space of the Milky Way beyond the boundaries of our solar system. First conceived by Dr. Frank Drake in 1961, the equation identifies many of the parameters and factors that can influence the estimate of civilizations we may discover. The idea of the equation was not to solve for the correct number of civilizations, but rather to generate discussion and dialogue among scholars at the SETI (search for intelligent extraterrestrial life). A pretty neat concept and equation! Here it is in all its glory

N = R* ⋅ fp ⋅ ne ⋅ fl ⋅ fi ⋅ fc ⋅ L

N =  The number of civilizations in the Milky Way Galaxy whose electromagnetic emissions are detectable.

R* = The rate of formation of stars suitable for the development of intelligent life.

fp = The fraction of those stars with planetary systems.

ne = The number of planets, per solar system, with an environment suitable for life.

fl = The fraction of suitable planets on which life actually appears.

fi = The fraction of life bearing planets on which intelligent life emerges.

fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.

L = The length of time such civilizations release detectable signals into space.

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Dr. Frank Drake and his Equation


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