In 1950, Enrico Fermi famously asked: “Where is everybody?” With humanity’s rise in technological progress, we could colonize the galaxy within a couple million years. If we apply the Cosmological Principle (We are not special) to our galaxy, the cosmos should be crawling with life. With over half a trillion planets in our galaxy and the notion that planetary societies are not rare, we should have run into a galactic civilization by now. Fermi wondered why we have no evidence fir life outside of Earth and offered his paradoxical idea. Fermi’s has at least ten solutions (see picture above), though they can be condensed into three broad categories:
We are the only galactic civilization and alone in the universe
Galactic civilizations are scattered about the galaxy, but no one has colonized it.
Interstellar travel is more difficult than we anticipated and societies are bound to their solar system
Human curiosity to explore is an uncommon trait
Civilizations are unable to handle their technology and end up destroying themselves before they are able to colonize.
There is a galactic civilization that has indeed colonized the galaxy but has not revealed itself to us.
Regardless of the solution, the paradox has two distinct outcomes: We are alone in the universe or there are other out there. Both of these answers are terrifying and hard for most people to accept. In a way, the next step relays on our future. Will we destroy our race and planet or will we rise above and take the first step in colonizing the galaxy?
In the last year or two, you may have heard the term ‘SpaceX’ pop up in casual conversation. You may have then asked yourself questions like “what is that?” or “who are they?” or “Is this another government moon landing conspiracy?”. Well, if you have, then I am here to briefly tell you exactly who they are, what they do, and why you should care.
First things first: Elon Musk. This man is a superhuman. Currently the CEO of not only SpaceX but also Tesla and Neuralink, as well as a leader in various other pioneering technology companies, this man does it all. If you want to know where advancements in technology are headed in the near future keep an eye on this guy. Anyways, his goal for the company SpaceX is simple: reduce the cost of space travel enough to enable the colonization of Mars. He believes this is achievable in either year 2024 or 2027.
How does SpaceX make money to fund such an ambitious project? Good question. They do so largely through an ISS (International Space Station) resupply contract with NASA, as well as contracts with the department of defense and other commercial companies for which they send satellites into space. All the while they are constantly improving their launch techniques and reducing costs. Just last month they completed the first relaunch and landing of a used orbital rocket. This is incredibly important because the orbital rocket is the largest and most expensive component of a space craft, and to make it reusable brings us all much closer to an affordable ticket to Mars.
All in all, SpaceX is one of the most exciting companies in the world right now. They have extremely ambitious goals and are already making history at an alarming rate. If you ask me, we’ll be putting a man on Mars very soon. Watch the video below to see their vision in color:
The ‘Goldilocks’ zone. More information here: Article
Earth is the only planet in our universe that we currently know supports life. For a planet to harbor life as we know it, it must lie in a star’s habitable zone. Being positioned in the zone is not enough, however. Countless planets orbit their suns at the proper distance and do not have life, including the planet Mars in our solar system. Why is the habitable zone so important for life? The so-called “Goldilocks zone” sits far enough away from a star that it does not experience intense heat, yet close enough that it does not reach extreme cold. This perfect distance allows water to condense as rain and form liquid oceans. As we know how fundamental water is to life, it is hard to know whether life could exist without it. Since our planet is our only sample size, it is a safe bet to search for life in areas we know they can thrive.
The Habitable zone varies on the size of the star. Stars with solar masses less than our Sun will have habitable zones much closer to the star since it has lower mass and luminosity. Likewise, a giant star has a habitable zone further than the Earth’s position. If a massive star existed in the Sun’s place, its high brightness and mass would radiate heat scorching Earth and warming Jupiter and Saturn to moderate temperatures.
The Drake Equation can be used to estimate the number of communicating civilizations in the milky way galaxy. First proposed by astronomer Frank Drake in 1961, the equation uses a series of variables to calculate the number of communicating civilizations, N. The variables each represent some cosmic parameter (mostly fractions) that influences the likelihood of existing civilizations (see below).
While some of these parameters are pretty well defined, many are up to the discretion and imagination of the scientist. For example, the number entered for the variable L can make a huge difference in the final number. An optimist who might believe that humans will last for millions of years will input a much, much larger number than someone who enters a number reflecting that the human race is past the halfway point. Either number is a fine choice–it is pure speculation. Therefore this equation, although interesting, cannot be taken as an accurate predictor for possible life within our galaxy.
A new study may explain these strange looking ring patterns on Venus’s surface. These geological markers are called coronae and occur when plumes of hot molten rock rise up and disturb the cooler material above it. The rigid surface is then cracked and molten rock can flow through cracks as magma. Scientists did tests in which they cooled particles of silica in fluid from above to simulate the way Venus’s surface cooled over time; next, they heated up the fluid below, observing the ways in which it rose and disturbed the solid above. Scientists also see evidence of plume-induced subduction, which occurs when the cool, solid rock falls into the cracks made by the hot plumes.
This is very interesting because previously, scientists were fairly certain that Venus had little to no geological activity anymore. It was compared to Earth in many ways, but never in terms of geological processes. This opens up the door for more investigation into how Venus may be more similar to Earth than we originally suspected. This can also teach us more about our planet’s past and formation; Earth could have undergone similar processes because it’s about the same size as Venus.
Ceres, the largest asteroid in the Solar System, and now considered a dwarf planet, may have once been habitable. NASA’s Dawn spacecraft collected samples from the surface and were found to contain organic compounds and amino acids, which are often referred to as the building blocks of life. Dawn has also discovered evidence of a subsurface ocean and cryovolcanoes. Cryovolcanoes spew out water, ice, and methane gas instead of the molten rock our volcanoes spit out.
This is a big deal for astrobiology because it further explores the possibility that the seeds of life exist throughout the Solar System and in the asteroid belt, specifically. There are theories that an asteroid crashing into Earth brought organic materials that would later form life.
Earlier this year, NASA approved two asteroid missions; one will be visiting Jupiter’s trojan asteroids and the other will be visiting a completely metal asteroid. It is thought that the metal asteroid is actually the core of a planet that had its outer layers destroyed by collisions. These missions will look for evidence of organic materials and amino acids, as well.
In the not too distant future, NASA will be sending a probe to one of Jupiter’s moons. I’m sure you can guess from the title of this blog post that the probe will be sent to Europa. Recently, NASA announced the name of this mission: Europa Clipper. It is named after clippers, swift ships that could make fast journeys across the Atlantic Ocean. Like the quick boats, Europa Clipper will be making around 45 flybys of Europa from as far as 2700 km to as close as 25 km over the span of a few years. Its primary purposes are to confirm whether Europa’s theoretical water ocean exists, the composition of the planet as a whole, and geological features of the planet. If said ocean exists, it would be an ideal spot for life in our solar system outside of Earth. The price of the mission is a hefty $2 billion, but its potential discoveries could be priceless. Since both the Democratic and Republican parties support space exploration, it appears as though the budget shouldn’t be an issue in the near future. Currently, a proposed launch date for Europa Clipper is sometime around 2022, but could be launched as early as 2020 with the right funding. Are you interested in what could lie underneath Europa’s icy surface? Do you think that life could thrive there? Would the life be microbial, huge, or something else entirely?
On our last day of class, I asked about the probability of life on Earth being the most intelligent kind of life in the Universe. I’ve always believed that the odds of our intellectual superiority must be incredibly low given the immense size of the Universe, but I’ve never really taken the time to learn more about any fact-based arguments that support this hypothesis.
In her explanation, Dr. G talked about how she believes that it is very unlikely that we are the most advanced life force in our Galaxy, let alone in the Universe. To explain this statement, she talked about how, due to our positioning in the Galaxy (far away from the center, with a lower concentration of Star Systems in our general vicinity), we were exposed to the heavy elements necessary for life to develop far later than other Star Systems closer to the center of the Galaxy, as these elements are exclusively created during supernovas. I’m sure that there are more arguments that point toward the conclusion that humans are unlikely to be the most advanced lifeforms in the Universe, but I appreciated the fact that this argument could be logically articulated in such a succinct way.
In many ways, this anecdote is representative of the personal significance of my taking Astro 2110. Throughout this class, my cursory understanding of all things extraterrestrial has been deepened, and I’ve been given the tools necessary to think critically about new discoveries in our Solar System and Galaxy. I was wary of taking this class in January, as nobody has ever accused me of having a scientific mind. That said, now that I have the requisite knowledge to keep thinking critically about the ever-evolving study of astronomy, I am excited to keep thinking about these issues. Great semester!
Recently, a NASA reported suggested that one of Saturn’s moons, Enceladus, could be a world that may be conducive to supporting life (source). Enceladus, which is covered in ice and significantly farther from the Sun than the Earth is, may not seem like a world where one might suspect life to be able to develop. However, it is believed that conditions may exist on Enceladus that are similar to conditions that gave rise to early forms of life on Earth, namely in the form of a kind of extremophile called a methanogen.
Methanogens are microorganisms that are believed to have developed in hydrothermal vents on the ocean floor, and are thought to be the earliest kind of life on Earth. They do not need Oxygen, and create methane by consuming Hydrogen and Carbon Dioxide (source). The Cassini mission has found that the conditions on Enceladus, which has a heated core and a subsurface ocean, are likely sufficient to support this kind of life.
To me, it is extraordinary that conditions on a distant, icy Saturnian moon may be, at least in some ways, analogous to some conditions on Earth (specifically with regard to hydrothermal vents and the subsequent development of methanogens). With the incredible amount of biodiversity on Earth, I would not be surprised if we continue to discover different kinds of extremophiles that may be able to survive in very disparate kinds of climates observed throughout the Solar System.
Saccharomyces Cerevisiae, also known as “Brewer’s yeast”, is a very strange extremophile. It is known as an “Osmophile”, or an organism that thrives in environments with high sugar concentrations. Many people fear osmophiles because they are responsible for the spoiling of many sugary drinks such as orange juice or soda. However, Saccharomyces Cerevisiae is a species loved by many due to its fermentation processes. Fermentation is the process that converts sugars into gases or alcohol. This organism is loved by aquaculturists because it is an easy way to deliver CO2 to underwater plants. It organism is loved by bakers because it is the source of the yeast that makes bread rise. Most of all it is loved by alcohol brewers (and college students) due to the fact that it is the main method of fermenting sugar into alcohol. Due to this last reason, it was also the first eukaryotic genome to be sequenced. It helped pave the way for the mapping of other organisms, including humans, which was finished in 2003. What is your favorite use of this organism? What do you think it could be used for in the future?