The Fermi Paradox

Posted on May 2, 2022 by jordanekstein

The Fermi Paradox attempts to describe why we have not made contact/found any intelligent life although the conservative estimate for how many intelligent civilizations there are throughout the universe is ten million billion. This theory is completely based on speculative math using the data we know about our universe. The paradox also describes Types of intelligent civilizations such as Type I (able to harness all the power of their planet; we are considered 0.7 of the way there), Type II (able to harness all of the power of their host star), Type III (able to harness all of the power of their galaxy). Due to how many intelligent civilizations there should be many of them would most likely be much older than us with an older star and would therefore be at one of these later stages. This then leads many to believe that the theory that none have reached out to us yet wouldn’t hold with the amount of individual civilizations there are that could reach out. This conclusion points many to the idea of the Great Filter.

The Great Filter: The idea that at some point between the beginning of its life and and Type III (when it could make contact with Earth) all intelligent civilizations hit a wall, or some stage in its evolutionary process that is near impossible to overcome. The Great Filter suggests either one of a few things. We could be rare meaning The Great Filter is behind us and occurred already. Whatever this may be must be a one-billion chance event. This leads to the Rare Earth Hypothesis that maybe the conditions of Earth and exact formation was truly the only way to create life.

Others think we are the first civilization and the conditions of the universe are optimal for the first time since the big bang for life to exist.

Another possibility is the Great Filter is ahead of us. This would civilizations commonly get to our stage in evolution but something eventually prevents it from growing. This could be a natural event such as a Gamma Ray burst or even the notion that once a civilization reaches a certain level of technology nearly all of them end up destroying themselves.

Another group think there are reasonable explanations for why we haven’t discovered Type II and III civilizations but that they exist. One explanation is that they have visited Earth but just so long ago there were not records and our lifetime as a civilization is not long enough yet to have experienced it again. Our galaxy may also have been colonized but we live in a very rural part of it and mostly desolate. Once Type II civilizations achieve the use of their star they have no need or desire to reach out to other civilizations that are more primitive. Another, really cool albeit terrifying explanation, is there are predator civilizations out there and most intelligent life knows better than to broadcast their existence and location. Similarly, there may be one super-predator that keeps killing off all the other civilizations. Higher civilizations may also be observing us or even kept from us by the government (conspiracy theorists maybe you deserve an apology:)! Higher civilizations may also be all around us but we’re to primitive to see them or understand what they’re doing. Finally (for now), we may just be completely wrong about our entire reality!

Overall, the Fermi paradox attempts to explain the fact that math points to there being ten million billion other intelligent civilizations and yet we have heard from none and have found no other life. Why?

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Future Visits to Solar System Worlds

Posted on May 2, 2022 by AndreaS
Image of the Europa Clipper that will study the potential for life on Europa.

Now that I have learned a great deal about the Solar System, I am looking forward to keeping track of the ongoing and future missions sending spacecraft to various worlds in the solar system. This post will outline some highlights of upcoming missions, as well as their objectives. Additionally, these missions are the ones focused on the planets of the outer Solar System and their moons.

Europa is getting multiple missions to assess its structure as well as potential for life with the European Space Agency’s (ESA) JUICE and NASA’s Europa Clipper. These missions will be launched in 2022 and 2024 respectively. JUICE will also observe Jupiter and its moon Ganymede and Callisto.

NASA’s Dragonfly is a spacecraft that will travel to Saturn’s moon Titan and sample atmosphere and surface composition. This mission’s objective is to study a world similar to Earth when life was just emerging on it, and will launch in 2027.

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Extremophiles in Space

Posted on May 1, 2022 by AndreaS

Extremophiles are lifeforms that can survive in what we would consider extreme conditions, such as very hot, cold, acidic, or salty environments. Since the various worlds we have observed in the Solar System are vastly different from Earth, astrobiologists predict that if any lifeforms exist in these places, they would be extremophiles. In this post, we will explore likely candidates for extremophile habitation in the Solar System.

Thermophile microbe that can withstand very high temperatures.

As we learn more about the moons of the outer Solar System, it is becoming apparent that there are likely multiple instances of subsurface oceans of liquid water. On moons like Europa that are heated by tidal forces enough to maintain internal heat, this could mean a habitat for thermophiles (heat-loving organisms) if deep sea thermal vents exist. Even without thermal vents, there are cold-loving extremophiles called psychrophiles that could live in cold places such as deep sea water and glaciers.

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Blog Post 8: The Golden Record

Posted on May 1, 2022 by isaachuggins
A picture of both sides of the Voyager Record. Credit to Smithsonian Magazine

The golden record is a collection of songs, messages, and symbols placed on a golden disk that was sent out on the voyager spacecrafts. The record also has imprinted on it a small encoded map about where Earth is or how far away it is, as well as messages telling whatever species that obtains this record on how to play it.

However, it should be noted that these sounds and records come from the 1977, an older version of America. Since then, our technology and capabilities as a species has increased exponentially. This record has no information on how the world is today, with the increasing use of the internet, the updates to human society, and how much more capable we are at sending messages across space. If an alien race found our golden disk, they might only assume that we humans are still at that level of technology and we cannot produce anything more advanced.

It would be a funny concept, if an alien civilization came to Earth expecting the same world as the 1970s only to be introduced to a Gen Z world with TikTok and iPhones. Furthermore, if we ever receive first contact, we should treat it as a lowball of how advanced the alien civilization is. Maybe for future probes going deep into space, more updated disks will be sent showing how far we have come.

Megatron holding the Golden Record. Don’t ask me how I know this, I just do. Source from ScreenRant.
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Blog Post 7: Drake Equation Odds

Posted on May 1, 2022 by isaachuggins
Drake Equation, as well as all of the factors that go into it. Credit goes to Business Insider.

The Drake Equation is an equation used to determine the odds of communicating with another alien civilization. Created by Frank Drake in the 1961, it was a product of all of the odds of life forming, planets having suitable habitats, and how successful the life was on the planet.

The first value was R, or how many sun like stars are in the Milky Way Galaxy that can have. The next following values are the odds of how many of these stars have planetary systems (fp) and how many of these planets are in the habitable zone of the star (ne). Fp is always high because evidence shows that the majority of stars develop planets from their accretion disks. Ne, however, has a higher range due to the situations of a terrestrial planet being in the habitable zone or a large gas giant with multiple terrestrial moons in the habitable zone. These two values could be estimated by looking at other systems and understanding planetary formation.

The other variables are much harder to accurately range. The odds of life developing, intelligent life developing, and such life developing communication technology are highly speculative. There is only one sample that we can use as reference for this one; Earth. Out of all planets, bodies, and systems that we have observed, Earth is the only planet that us humans have discovered life on.

Although this could be due to pessimistic bias, but the odds of life forming is fairly small, since scientists have failed to create life even under ideal circumstances. The results may improve through time, but it appears to be a random chance occurrence rather than an eventuality. For such life to become intelligent, there needs to be enough competition in the ecosystem to force evolution to evolve sentience. This took Earth 3.7 billion years, and the odds of life randomly going extinct also make this value smaller. Finally, there is the odds of such life developing communication. There is no inherit need for a species to look to the stars apart from curiosity and looking for more resources, and the odds the alien species thinks like us is very slim.

The final variable is L. This is how long a civilization can exist without self imploding or losing to natural causes. This is probably the lowest. A competitive alien species would develop weapons in order to survive and adapt. Us humans have always been inventing new weapons to give us a new edge against ourselves. We developed nuclear bombs at around the same time as we sent out the first radar signals. We used said nuclear bombs before we ever set a man on the moon, and we have had multiple wars since. It is my unfortunate conclusion that an advanced alien race would also face these issues and go extinct quickly.

Due to all of these low percentages, the odds of communicating with life is slim to none, and this is for the whole Milky Way, not just some nearby star system. As pessimistic as this seems, it also is quite special, since it shows despite these low odds, we as humans are somehow here. We managed to beat the odds, and our mere existence is something of a miracle.

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Throwing Rockets Into Space Using A Skyhook

Posted on May 1, 2022 by josephmaquino9
Figure 1. Skyhook concept where a space shuttle is attached to a satellite in orbit (via tether) and is hurled away from Earth.

One of the biggest issues with rocket launches today is the inefficiency of converting fuel into thrust. Because of this, rocket payloads have to be small compared to the amount of space required for fuel. For instance, the SpaceX Falcon Heavy rocket carries a total weight of fuel of ~411 tonnes (the equivalent weight of 2.5 average-sized American homes). Clearly, we must look at alternative methods of guiding a rocket into space and away from Earth while allowing for more space for a payload.

Enter the concept of a “skyhook”. The idea behind a skyhook is to have a satellite with two attached tethers: one long tether with a hook that can attach to an incoming spacecraft and another short hook with a counterweight. As shown in Figure 2, if one can get the satellite’s orbital velocity to synchronize with the tether rotation rate, then the tether’s tip will move as a cycloid curve. There are two key characteristics of a cycloid curve that will help us understand the idea behind a skyhook. First, when the tether reaches its lowest point, it is essentially stationary. Here, an incoming spacecraft can safely attach to the skyhook. Second, at the tether’s highest point, the velocities of the satellite and tether are working in the same direction. This means that this point serves as the location at which the skyhook is traveling at its fastest speed. Thus, releasing the spacecraft here would allow it to slingshot away from Earth at high speeds.

Figure 2. An example of a cycloid curve for a rotational system.

So, what would be a concern of utilizing such a system? Skyhooks are also referred to as “Momentum Exchange Tethers”. This is because the rotational momentum from the satellite is transferred into the attached spacecraft as the spacecraft is accelerated. Over time, if rotational momentum is not added back into the satellite-tether system, the system would eventually stop spinning. To prevent this, the skyhook would either have to have on-board thrusters that could burn for a specific amount of time (allowing the system to regain rotational momentum), or the skyhook would have to be capable of slowing incoming spacecraft down for a descent to Earth. The latter option means that the momentum from the fast-traveling spacecraft would be added to the satellite-tether system.

If we are able to successfully design, construct, and deploy these skyhook systems, a great amount of money and space on rockets can be conserved as the required amount of fuel to complete a space mission would decrease. This would also open the doors to incorporating skyhooks across the Solar System (i.e., around the Moon, around Mars, etc.). Accomplishing such a feat would allow for a more constant stream of rocket launches to occur.

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Asteroids and nucleotides | blog VIII

Posted on May 1, 2022 by clviggiano
NASA

Just five days ago, researchers identified the last two nucleotide bases in asteroid samples that had previously been unrecognized. Professor and researcher Yasuhiro Oba at Hokkaido University in Japan, alongside a team of scientists, successfully identified the missing cytosine and thymine nucleases. Unlike the other bases, Cyt. and Thy. have very delicate structures, making them more difficult to distinguish in meteorite samples. This discovery confirms the presence of all five nucleotides on asteroids, which are the bases of DNA and RNA—the bases of life. Organizations and science magazines that have reported on Oba’s findings are suggesting that this discovery revealed the ‘blueprint’ of life. 

Of course, there are many more questions remaining than there are answers to satisfy them. One of the main uncertainties is how exactly the nucleotides were transferred from their source asteroids to Earth. There are two hypotheses to explain this transference. One suggests that meteorites directly introduce them to Earth’s surface through impacts with the planet. The other delivery is attributed to meteoric smoke, which is a vaporized form of solid matter that then condenses at low altitudes in gaseous atmospheres; this particle smoke occurs when the meteorite enters and burns in the atmosphere. This theory posits that the nucleotides are carried via this meteoric smoke, which then is deposited on Earth’s surface as the particles settle. These hypotheses are not mutually exclusive, and may even occur as two phases of a meteorite’s contact with Earth. Right now, the specifics of how these nucleotides are transferred from asteroids to Earth are not the most important part of this discovery. Rather, it is the newfound confirmation that the building blocks of organic life can and do form in space.

Universe Today
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Bracewell “Messanger” Probes

Posted on May 1, 2022 by josephmaquino9
Figure 1. Depiction of the hypothetical Bracewell probe.

In 1960, Ronald Bracewell made public his idea of a “Bracewell probe” that was capable of both identifying and exchanging information with intelligent alien civilizations. These probes would be sent toward different star systems and place themselves within a near-circular orbit in a star’s habitable zone. Using solar energy from the star, the probe would power its electronics and continuously scan for narrow-band radio transmissions within the star system. Should any transmission be identified, the Bracewell probe will locate the source of the signal and send the original signal back in hopes of gaining attention and establishing further discussion between the probe and civilization.

There are several advantages of having a probe with the described characteristics. First, placing a probe direction in a star system allows for a more powerful signal to be transmitted as opposed to transmitting from Earth (being light-years away). This means that the signal would be much more noticeable for advanced civilizations that are capable of detecting these signals. Another advantage is that this probe could remain in orbit around the star of interest for a long period of time. If initial broadcasts from the probe generated no response, new messages across a variety of frequencies could be emitted to increase the odds of contacting these civilizations. Finally, placing a probe directly in a star system allows for near real-time communication. This eliminates the issue of sending and receiving messages that are several years old.

Perhaps the Bracewell probe is our answer for locating other advanced civilizations; however, two main obstacles exist with current technology. One issue is that we currently do not have the propulsion methods for getting these probes to a location in a reasonable amount of time. There have been advancements with nuclear fusion propulsion units, but these units have not been fully developed. With current propulsion methods, fuel would be exhausted long before we would attain speeds that would get us to these star systems in a timely manner. The second problem is that the probe requires a high degree of artificial intelligence. Even though real-time conversations can occur between the probe and an advanced civilization, it will take a while for this information to be relayed back to Earth. Therefore, the probe must be capable of carrying a conversation without having human input. When these problems are addressed, finding extraterrestrial life can become a reality.

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Acidophiles, pH, and life on Venus | blog VII

Posted on May 1, 2022 by clviggiano

The pH scale is used to gauge the acidity and ranges from 0-14, with lower values being more acidic and higher values being more alkali. 7 is the neutral level between the two. Substances like battery or stomach acids have pHs around 0 or 1; water and blood are around 7, with drain cleaner or bleach being the most alkali at a pH of 14. Everything on Earth with a measurable pH falls somewhere on this scale. However, these limits do not apply in our solar system. The clouds that comprise Venus’ atmosphere are made mostly of sulfuric acid, ranging from concentrations of 75-96% in different areas and elevations. Their pH falls below the Earth scale to an incredible -1.2. To date, this is the most acidic substance ever discovered, and reflects the extremity of extraterrestrial conditions. 

Acidophiles on Earth favor conditions with pH values under 5, making oceanic volcanic vents and sulfur springs suitable homes for these microorganisms. However, it seems they grow most successfully when the pH is approximately 3. This raises the question—to what extremes could life survive? Is an environment of -1.2 pH too acidic even for acidophiles? Could even this harsh planet support some kind of life? For the moment, these questions remain unanswered. Yet the presence of acidophiles on Earth raises it as a very real possibility. 

On a final note, achieving a calculated negative pH level is actually quite simple; it occurs when the hydrogen ion concentration of the substance reaches a molarity greater than 1. However, testing whether the substance actually has a negative pH is incredibly difficult. There is no litmus paper or method to confirm that the calculation matches the true pH. This being said, the true acidity of Venus’ clouds is not known with certainty, but is simply a calculated value. It is possible that solar pH levels are much higher or lower than currently-known values.

Sulfuric acid clouds on Venus. JAXA/ISAS/AKATSUKI PROJECT TEAM.
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KB’s Astronomical Review

Posted on April 30, 2022 by Karan Bhardwaj

Over the course of the semester, I have significantly improved my understanding of space, the stars within, and the 8 planets of our solar system. It was particularly interesting to me discussing the formation of the solar system, as I had no idea there were so many unique events that shaped our solar system to be how it is today. (For example, the Moon being made out of Earth’s crust that was blown away.)

When I look at a picture of space, or look up into the sky, I now wonder what solar systems the stars above hold, when we will reach them, and if they’ll respond to the radio communications humans have sent out. Additionally, I wonder if the gold plaque’s sent out into space will ever be recovered, by either humans or aliens.

Looking into the future, I am excited for what the future holds. Specifically, future probes to the solar system. I distinctly recall looking at the Mission Juno ‘time until destination’ multiple times while I was in high school, and reading about the mission in our textbook was extraordinary. For the future, I hope that we are able to send out many, many probes that bring back information that leads to more answers about the universe.

Jupiter’s South Pole, as seen from Mission Juno.
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