Drake Equation

Posted on April 30, 2023 by niqretnuh

How many civilizations are there in our galaxy? As a kid, I was awestruck by the knowledge of just how small we are as compared to the universe. The concept of “me” is nothing more than a tiny stardust living in 1 of the 100 billion star systems in our galaxy. However, if there are 100 billion stars in the Milky Way, how likely is it that there are millions of civilizations out there just like us? I have always thought that there would be no way of knowing this, since how can we detect new civilizations if we cannot even fly out of our solar system? However, the Drake Equation might help us get an estimate of this question that we, as a species, may never know the answer to.

In 1961, an astrophysicist named Frank Drake developed the “Drake Equation” to provide an estimate of how many detectable civilizations there are in our galaxy. In this equation, we can fill in a series of variables to get an estimate, N, that represents the number of civilizations. 

The uniqueness of the Drake equation is that instead of asking the question, “are there civilizations out there”, it asks, instead, “are there any other technologically advanced species other than humans that has ever existed in the galaxy”. What I loved most about the equation is the “L” factor, which stands for the length of time a technological civilization can stay for. For my estimate, I used the length of the dinosaur – 165 million years – as the estimate, optimistically hoping that we as a species can sustain as long as the dinosaurs have. Another interesting addition to the Drake equation can be a “recurrence factor”, where we include the probability of a civilization repeatedly happening on a planet. 

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Seager Equation

Posted on April 30, 2023 by oilrigatoni
Pexels

So the Seager Equation was made to mimic Drake’s Equation. It doesn’t find communicable aliens, but rather just that life which is detectable from Earth. It also doesn’t specify intelligent life, so it searches for any discernible life at all, from microbes to megafauna. The equation goes like this:

N* : Number of observable stars x

FQ : Fraction of those stars with minimal activity x

FHZ : Fraction of those stars with rocky planets within the habitable zone x

FO : Fraction of those planets that can be observed x

FL : Fraction of those that have life x

FS : Fraction of those that produce gaseous bio-signatures =

Number of planets observable planets with life. (Ghost Theory)

There are some obvious practical concerns with this equation. The number of observable stars is a tough number to get a hold of. Although there are around a septillion number of stars in the universe, we can only see a fraction of that. The mission Gaia is monitoring around 1 billion stars, so it is definitely at least that many. (Space)

Those stars with minimal activity includes those with infrequent and small solar flares and radiation expulsions. These large radiation bursts would destroy atmospheres and any hope of life forming.

Planets with gaseous bio-signatures would include, likely, a significant portion of oxygen. But the limiting factor here is that we assume life would produce large amounts of oxygen, which is not necessarily true. That is only if they use similar processes to our own. Gaseous water is also likely, but again that assumes Earth-like analogs. So any guesses we have are purely from the Earth standpoint.

Essentially, we have a start for how to start looking for life, but we won’t ever be certain until we find it. Life is extremely adaptable, and can take many possible forms. So to narrow down what life would look like is extremely hard. But if we were to find life on Titan or Europa, a lot of our current assumptions may change.

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The Apollo 11 Quarantine

Posted on April 30, 2023 by Trevor Pillow
The Apollo 11 Astronaut Quarantine

When Neil Armstrong, Buzz Aldrin, and Michael Collins returned from space after the Apollo 11 moon landing, they were immediately placed into a quarantine. This was the first manned mission to the moon, and the scientists weren’t sure if there would be any dangerous particles on the moon that the astronauts might bring back to Earth. In fact, the astronauts were surprised at how much moon dust stuck to the mission components. The regolith “went everywhere and attached itself to everything in sight.” Nobody was positive how toxic the dust would be, so to be 100 percent safe, the astronauts were placed into quarantine.

The secondary reason for the astronaut quarantine was due to the possibility of alien microbes attached to the dust. Nobody was sure if there was any life on the moon yet. Extremophile bacteria had already been observed surviving in environments similar to space, so it is not too outlandish to suggest that microbes could survive on the moon. It is also technically possible that these microbes could make it back to Earth on an astronaut. So, the quarantine is designed to protect people from any possibly dangerous microbes as well as protecting the possible microbes themselves so that they may be studied.

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Fermi Paradox

Posted on April 30, 2023 by shuhuaiwang

When ordinary people ask, where are the aliens? We usually just laugh it off and take it as a joke. However, when this sentence is uttered from the mouth of a scientific authority, it becomes a question that is terribly thoughtful. The sun is a relatively young star, which means that there are terrestrial planets that are much older than the earth. In theory, their civilization should be far more developed than ours. Earth is 4.54 billion years old. Assuming we compare with a planet P which is 10 billion years old. If P’s experience is similar to that of Earth, their civilization should be 5.46 billion years ahead of us. Their technology will be beyond our comparison. This gap is like the monkey seeing human civilization. So why haven’t we discovered alien civilization so far?

One explanation for the Fermi Paradox is that alien civilizations tend to self-destruct before making contact with other civilizations (such as Earth). e.g. climate change, nuclear war

Another explanation is that intelligent civilizations are rare, either because the conditions necessary for the evolution of intelligent life are scarce, such as humans needing oxygen to live.

Or the alien civilization has received the signal sent by the earth, but they may not reply to us for some reason.

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Blog #8 – Black Holes and How to Find Them

Posted on April 30, 2023 by constellationsarentreal

Black Holes are quite a popular topic in astronomy, but I still would like to talk about them for my last post, since they are truly revolutionary. Black Holes, in short, are gravity’s ultimate victory over stars. After a star supernova explosion, the core of a star remains. But if this core weighs more than 3 solar masses, gravity overcomes the neutron degeneracy pressure, causing the star’s core to collapse into oblivion and form a black hole! The star becomes infinitely small, but still contains its mass. While its finite mass is still there, the black hole has no physical dimensions! Within the event horizon of a black hole, Newton’s 3rd law is no longer valid. This singularity at the center of the black hole cannot currently be explained by physics and mathematics.

Of course, you can’t talk about black holes without mentioning Einstein’s theory of relativity. According to his theory, gravity is actually the warping of space-time around an object with mass. Einstein asserts that even light, although it has no mass, is affected by gravity. As such, gravity around a black hole imposes a curvature in space that bends light. Within the event horizon, light cannot climb back out. As matter approaches the event horizon, tidal forces are intense and “spaghettify” any object. Contrary to media depictions, black holes do not “suck” things into them. Black holes, like any other object according to Newton’s law, exerts gravitational force. Gravity only deviates from Newton’s law at the Schwarzschild Radius (distance from a black hole when escape speed equals the speed of light).

Finding black holes is just as interesting. We can detect them in X-ray binary stars (where matter from one star falls onto another). Astronomers observe orbiting planets experiencing tidal disruption, where matter heats up as it falls in a gravity well, emitting X-ray light for us to detect. However, we cannot see the companion star where all the matter is falling. Kepler’s 3rd law tells us that the mass of said unseen companion is greater than 3 solar masses, but it can’t be a neutron star otherwise we would see it. The only thing that massive, but small enough to be invisible, is a black hole!

The first ever candidate for this procedure was Cygnus X-1, a binary star system. The left image depicts its location within an active star-forming nebula. The right image is an artistic depiction of matter from the companion star falling into the black hole.

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Blog Post 8: How astro2110 Has Changed My View On Astronomy

Posted on April 30, 2023 by Myles7235
Star Gazing

Before coming into astro2110, I knew very little about astronomy. Now, after completing the course, my appreciation for astronomy has greatly increased. A few days before the semester started, one of my friends who is an astronomy nerd laughed at me for not knowing the phases of the Moon. I thought to myself, “I’m a CS nerd, why would I need to know the phases of the Moon”? I had forgotten just how interesting astronomy is as a whole. Never had I sat down and actually thought that there’s more to astronomy than just the phases of the Moon. There’s the Milky Way , and extremophiles, and dwarf planets, the Kuiper Belt, moons of other planets, constellations, nebulas, aliens, space missions, and much more. Learning about all of these topics and more makes me excited to learn more in the future. The galaxy is way bigger than I thought, and we’re just a mere speck in the midst of it all. Which means that I still have tons more to learn about what’s here on Earth and what is out there beyond the stars. Watching the lecture that Alan Stern gave about the New Horizons mission visiting Pluto refueled my curiosity about space exploration. The fact that we don’t know what’s out there and we’re constantly learning new things has influenced me to continue to keep up with astronomy in the future. Now I can go back to my friend and tell him every single one of the phases of the moon and maybe even throw one of my own astronomy questions at him.

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Until Next Time!

Posted on April 30, 2023 by sadiekarr

(Tatooine’s “Twin Suns“)

I have always thought that astronomy and everything to do with Earth and outer space were so freaking cool (and terrifying), but it wasn’t until this year (taking both ASTR 1010 and 2110) that I got to really dive into the area of study.

It’s a lot harder for me than some to draw connections between astronomy and my choice of major (I’m studying English literature), but I have been absolutely delighted by the amount of connections I’ve been able to make with various fantasy and Sci-fi fandoms I’m a part of (Godzilla, Star Wars, various video games and books, etc). I am a HUGE fan of fantasy and sci-fi worlds and stories and few things bring me more joy than nerding out about them. Being able to see real-world and scientific elements in some of my favorite fictional worlds has been a very fun aspect of studying astronomy.

I’ve gotten to compare Godzilla and other Kaiju to extremophiles, gain greater understanding of light-speed travel capabilities (we are no where near hyperspace travel, that’s for sure), and got to calculate the damage of an asteroid hitting my home town. That last one, while unbelievably cool, brought back some unpleasant memories of my viewing of the 2020 film Greenland (it is very good, you should watch it, but it was slightly traumatizing for me)

I have enjoyed this class so much and know that my astronomy journey will not end here- maybe my academic astronomy journey, but not my interest in it lol!

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Blog Post 7: What Will Happen If We Do Find Life Out There In Space?

Posted on April 30, 2023 by Myles7235
Alien

The common question when thinking about life in space is always “Is there even life in space”? But few people think about what would actually happen next if we were to find life out there beyond the stars. If we ever do receive a message from extraterrestrial beings, many people have this vision of it being a greeting message. The aliens will have decoded our friendly message that we sent to them and they’ll send a nice response in return, right? As time has progressed, some astrobiologists have started to believed that this is the optimal outcome. First we have to be able to decode the message. Let’s imagine that we don’t decode the message though. Could it be for our own good? The aliens might not send back a message as pleasant as ours. It may contain something devastating that could alter the future of Earth.

The bigger question that people are starting to ask now is “What will the alien’s message say, and will it be friendly”? Some people believe that the message will be a call to action to help humans. Aliens most likely have far more advanced technology than us humans, especially if they can figure out how to send a message from a different star system. They may instantly recognize the information in the messages that we send. It is possible that they will send a message telling us that our technology is lagging behind theirs and offer to lend a hand. There are others that believe if we receive a message like this, it could be a trap. The alien’s could act benign, but end up secretly waging war and plan to destroy the human race. Think of it as it as here on Earth. Another place has other living beings and resources on it that a certain group may want to control. Or, you find a group of beings that you know little to nothing about in a place where you thought you were alone. That could spell bad news for us.

So before you get too excited about finding extraterrestrial life, think about the possible outcomes. What would the aliens do? What would Earth do in response? What would you do? If you’d like to learn more about the possibilities of finding extraterrestrial life, you can visit this site.

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Maybe Signs of Alien Life Would Not be Good a Thing

Posted on April 30, 2023 by thisisntzenon

When acknowledging the vastness of our universe, it is inevitable think that alien life must be somewhere. The Fermi paradox has addressed just this; however, in todays blog I would like to consider the scenario of the paradox being solver. In other words, what could go wrong if we finally found intelligent life outside of Earth.

Video Discussing the Dark Forest Solution to Fermi paradox by In a Nutshell

In a Nutshell outlines the Dark Forest solution to the Fermi paradox. At the forefront, the human race has so far one the competition in establishing dominance on Earth. According to Pierce (2015), a specific number has not been identified as far as global daily extinction rates go, but the general consensus is our dominance over the environment actively results in the death of species unable to compete. Thus, the Dark Forest solution contemplates that if we discovered intelligent life we could enter ourselves in the competition of our lives. As we communicated across such large distances, we may not be aware of the power or intentions of those we found.

This particular solution begs the question: Would discovering other intelligent life be worth our safety?

What do you all think?

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Launching Spacecraft with Nuclear Bombs

Posted on April 30, 2023 by Trevor Pillow

You might be familiar with the Orion Spacecraft, which is the vehicle being used in NASA’s Artemis series of lunar missions. However, have you ever heard of Project Orion?

Most conventional spacecraft are propelled using chemical reactions which create high velocity exhaust that is focused through a rocket nozzle. Newton’s Third Law dictates that the force of the exhaust leaving the nozzle must be met with an equal and opposite force resulting in the spacecraft accelerating. The main limitation of this design is the fuel density of rocket fuel. In order to get further into space, you must bring more fuel. Bringing more fuel into space requires even more fuel. The diminishing returns make it difficult to bring a large mass into space.

In the 1950’s, NASA and DARPA theorized a new propulsion system for large rockets: nuclear explosives. Rather than chemical reactions propelling the rocket fuel, a magazine of nuclear bombs detonate one after another. The resulting energy propels gas out of the rocket, achieving the same end result as the conventional rocket. However, the energy density of nuclear bombs is much greater than rocket fuels like kerosene. A 1 megaton bomb can weigh as little as 680 pounds. Using as few as 300,000 bombs at 1 megaton each, a spacecraft could theoretically achieve 3 percent of the speed of light. Such a spacecraft would be able to reach Alpha Centauri in 133 years.

Project Orion was eventually abandoned due to concerns involving nuclear fallout in space. More realistic nuclear propulsion devices have since been theorized and prototyped. Rather than using nuclear explosions, these much more boring rockets just use nuclear reactions to heat hydrogen that acts as a propellant.

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