What is Stromatolite? It is a layered deposit made mainly of limestone. They are known to be thin and alternate from light to dark layers. They were common in Precambrian time which is more than 542 million years ago.
Where can you find them? They grow in areas such as Shark Bay in western Australia, Brazil, the Bahamas and Mexico.
Shark Bay, Australia
Why are Stromatolites interesting? Although they are rare today, fossilized stromatolites provide records of ancient life on Earth. They are an important source of information on the early development of life on Earth and possibly other planets.
Posted inClass|Taggedastro2110, blog7|Comments Off on Stromatolite Structures
Sokka, from Avatar, the Last Airbender. Curtesy from The Nerdist.King Tutankhamen’s golden sarcophagus, curtesy ThoughtsCo.
Avatar the Last Airbender has received a surge of popularity in the past few years, as it is considered one of the most popular cartoon shows to ever air. One of the characters, Sokka, is a teenage boy from the Southern Water tribe and has multiple tools and skills, like his boomerang, to save the day.
King Tutankhamen was a boy king of Egypt during the New Kingdom, around 1300 BC, according to Wikipedia. He died when he was still a teenager, around 19, and was buried in the Valley of the Kings. His tomb would remain unraided and perfectly preserved until Howard Carter discovered it in 1922. Although King Tut was not that important in terms of history of Egypt, he is still one of the best preserved and most documented pharaohs we have from history.
So what do these two people have in common and why the hell am I talking about them in an astronomy blog? Well they both happen to have a side arm, Sokka has a sword and King Tut had a dagger. There is strong evidence that suggests that both were made out of meteorites.
Sokka receives his sword in an episode focused around him learning from a sword master. At the beginning, there was an meteor impact that happened near a town, and the gang had to stop the fireball. However, due to our previous homework regarding impacts, a meteor of that size would have done much more damage to the surrounding area, and almost all members of the crew would have been killed or severely injured. However it’s a kids cartoon, so I will say that this is acceptable.
King Tutankhamen was found with many gold artifacts, sarcophagus, and weapons to prepare him for the afterlife. Near his body, he had a gold dagger and an iron dagger. This would not have raised any suspicion, except this was the bronze age and true iron forging techniques developed much later. Egypt also referred to iron as “iron from the sky,” and the material in pure form was more valuable than gold at the time. Researchers further analyzed the dagger recently, and in 2018, a paper was published about the true composition. The dagger had trace amounts of iron, nickel, and cobalt, according to History. These three elements are commonly found in meteorites, giving more validity to the theory that this weapon was from a meteorite.
Though this does not contribute to learning more about stars and our solar system, it does show that we as humans have always been fascinated by what lies beyond our sky. Ancient Egyptians had revered such fascinating objects, and even in pop culture today meteorites and space still just as amazing. In fact, multiple people recently have been inspired to take meteorites and turn them into art, such as jewelry, paperweights, or even more swords.
Yoshindo Yoshiwara’s sword forged from the Gibeon Meteorite, credit for image to TheNerdist.
Other than life on Earth, is there any other planet in the Milky Way which might harbor life intelligent enough for inter-stellar communication? Many approaches to this question, with different philosophies have come to fruition throughout the years. One such approach is the Drake Equation:
There are 7 different parameters to the Drake Equation, considering things like how long a civilization might be broadcasting communications, the fraction of civilizations formed that can communicate via detectable signs, the fraction of planets that could support life, etc. Various solutions to the equation have been determined, with one of the largest variables being L or how long a civilization is broadcasting communications. The longer a civilization broadcasts, the higher the resultant product. Drake himself theorized N = 10,000 or so, other estimates put N at 15+ million, and the lowest estimates have N << 1.
However, other ideas of life on other planets may prevail. A heated debate about GFAJ-1, a bacterial cell that was said to be able to use arsenic in place of phosphorus in its backbone, may provide a clue. While the actual bacteria is dependent on phosphorus, life on other planets might be able to use other elements to preserve information.
I think one of the most interesting things about the moons of our Solar System is their names. We have named planets after the Greek Roman gods, and most of their moons after characters from myths that relate to those gods. For this post, I will be focusing on the planet Jupiter and the names of the moons that orbit it. To begin, the name Jupiter means “the supreme god” and is representative of the Greek Roman god Zeus, the king of Olympus. The moons were named after his lovers, which he had relationships with despite being married to his wife, Hera/Juno.
The largest of Jupiter’s moons is Ganymede. According to Roman mythology, Ganymede was a handsome mortal that Zeus abducted and brought to Olympus to serve as a cupbearer to the gods. The second largest is Callisto, who was a beautiful nymph that was also known to be the daughter of the King of Arcadia. Zeus loved her but, due to her Vow of Chastity to the Goddess Artemis, he decided to turn her into a bear. The third largest is Io, who was known as the first priestess of Hera. However, when she became Zeus’ lover, he turned her into a white heifer to save her from Hera’s wrath. The last moon that I want to talk about is the fourth largest, Europa. Unfortunately, her story is not a happy one just like many of these myths. Zeus tricked, raped, and impregnated her and she ultimately gave birth to Minos who would become the King of Crete.
The myths surrounding the moons of Jupiter are all extremely interesting, and I encourage everyone to look into them if they have any interest in Greek or Roman mythology!
Jupiter’s Moons: Io, Europa, Ganymede, and Callisto
Some of the most well known moons in our Solar System, aside from our own, are Jupiter’s Moons. They are known as Io, Europa, Ganymede, and Callisto. However, there are over 170 known moons that orbit all of the Jovian Planets. Jupiter and Saturn both have over 60 each that range greatly in size, and Ganymede and Saturn’s moon Titan are both larger than the terrestrial planet Mercury. The compositions, however, between the terrestrial planets and Jovian moons are very different. The moons contain a lot more ice than the planets, in addition to metal and rock. This is because they formed farther away from the Sun. It is also widely believed that they formed by accretion within the disks of gas that surround each of the giant Jovian planets. This would explain why they orbit in the same direction as their planet’s rotation.
Some of Jupiter’s moons are surprisingly geologically active! Io specifically is volcanically active, even more so than any other celestial object in our solar system. The surface of the moon is so young due to the constant repaving with lava that we cannot find any evidence of any impact craters. The volcanoes are similar to those on Earth and produce outgassing just like on our own planet. This is what makes Io one of the most interesting moons that we have studied, and why it shatters the common idea that all moons are barren and geologically dead.
The words in the above picture are hard to make out, but I really liked the visual of some of the known exoplanets graphed on a plot. The color and appearances of these planets are not truly known since we have not directly seen them, but they are inferred based on density, temperature, metal content, and comparisons to our own solar system. The rings on some planets are just for the aesthetic, but since the large planets of our solar system have some kind of ring formation, it is likely that this pattern exists elsewhere.
Now that I have partially explained the diagram, let’s get into what an exoplanet is. The definition is pretty straightforward: a planet outside of our solar system. Much like our sun, other stars have planetary systems or planets. While the exact number is not known, there are 5,011 confirmed exoplanets, 8,738 candidates, and 3,763 planetary systems (at the time this post was written). While there is currently no proof that life exists beyond Earth, with so many stars and planets in the universe, it is hard to believe we are alone. There are even exoplanets that have similar conditions to those of Earth and are believed to be habitable.
There is something called the Goldilocks’ Zone where certain conditions that are suitable for life might be met. One of these is a distance from their sun where it is warm enough for liquid water to exist on the surface, like on Earth. Scientists also look for rocky planets, since these are more likely to host life than a gas giant. Different stars have different habitable zones depending on where they are in their lifetime and their temperature. While life on other planets has not been discovered, I believe that there is something out there.
One of the preeminent methods for finding exoplanets is tracking periodic variations in stellar brightness. In class, we practiced this technique by examining the light curves of certain variable stars and identifying the presence of orbiting exoplanets. In the real world, scientists must first identify variable stars and then determine which of these variable stars’ brightness fluctuations are actually due to orbiting exoplanets, before they can conduct light curve analysis.
This school year, I have been conducting research on variable stars using data from TESS (Transiting Exoplanet Survey Satellite). My job is to help implement a machine learning algorithm to classify variable stars based on up to 63 stellar characteristics. In the TESS database, each star has information on its mass, radius, period of brightness fluctuation, average luminosity etc. The algorithm’s objective is to analyze existing variable stars (whose types are known) and decipher patterns that differentiate variable star types. Once the algorithm is working effectively, it will be able to process new observations and accurately label each variable star by its type. This type of data processing is vital to identifying exoplanets in the future. As an example, scientists could use this algorithm to effectively ignore all variable star types whose brightness fluctuations are not due to transiting exoplanets. Additionally, if scientists figure out which type of variable star most frequently hosts exoplanets, the algorithm could help scientists focus their time on the stars most likely to be host to exoplanets.
I have not yet completed my research; however, I have been able to create a machine learning algorithm that identifies the most important stellar characteristics for classifying variable star types. Additionally, I have had some success classifying variable stars to a moderate degree of accuracy. While my research is coming to an end, other individuals have (and will) create similar algorithms to help astronomers interpret data from upcoming all-sky surveys. Machine learning algorithms, such as the one that I worked on, will be integral to future astronomical discoveries.
There are many moons of Saturn, but the two largest are Titan and Enceladus. Titan is an enormous moon, the second largest in the Solar System after Jupiter’s Ganymede. It is notable for its thick atmosphere, which is made up of mostly Nitrogen compounds. Its surface is characterized as geologically young, with evidence of lakes and other surface liquid features that are likely made up of hydrocarbons.
Enceladus is a much smaller moon, about 1/10 the size of Titan. It has a snowy and icy surface that contains both very old and very young terrains. Heated by tidal heating, there is evidence of recent ice volcanoes, and the fresh material makes Enceladus the most reflective object known in the Solar System. Enceladus is also thought to have a liquid interior, further evidence for a source of heating and active geological processes on the moon such as tectonic activity that produces the large rifts and scars that can be seen along the surface.
Comets are relatively small bodies in our solar system comprised of dust, rock, gases, and ice. They are remnants from the formation of the solar system, and their solid bodies, or nuclei, can range from a few miles to dozens of miles wide. When its orbit gets close to the sun, this nucleus heats up and forms an atmosphere, called a coma, and a tail made of gas and dust particles facing away from the sun that can be millions of miles long. There are currently 3,743 known comets in our solar system, but it is estimated that billions exist in the Kuiper Belt and Oort Cloud. We can usually only detect comets whose orbits come near the sun since this is when the coma and tail form. The comets in the outer solar system are too cold to release this large stream of gas and dust, so they are harder to detect. Despite this, comets have been discovered near other stars in the Milky Way, and probably exist throughout the universe.
If you’re like me, you’ve heard plenty about black holes, but your only real understanding comes from a couple Interstellar screenings. The movie does a pretty great job being accurate, but even the excessively brilliant characters don’t know whats going on behind the scenes. This blog is an exploration of the phenomena, equal parts for curiosity and so I can stand my ground when I mention I have a minor in astronomy.
To me, the name “black hole” is somewhat misleading. There’s no expanse or hole to fill, but rather an excess of mass that is super tightly packed. The hole in question is actually what all of that mass does to spacetime, our way of conceptualizing the intersection of time and space. The intensely concentrated gravity drags down that fabric of reality, creating a deep pit that even light can’t climb out of, earning the “black” of black hole.
Visualization of effect on spacetime
Due to the trap that black holes set for light, they’re difficult to detect. It turns out one of the easiest ways to pick up on them is to recognize what they’re known for: gravity. Observing inconsistencies in orbits and trajectories can sound the alarm for a black hole pulling the strings behind the scenes.
