The Terrestrial Worlds

Source: Here

The planets of the Solar System dramatically vary from massive gaseous, ringed giants to
miniature rocky terrestrials. The celestial bodies are also at such great distances that no map of our Solar System can truly illustrate both the distances and relative sizes to scale. The terrestrial planets are relatively similar in size and composition, but interestingly, their atmospheres could not be more different.

Cool Solar System Scale Video!

Atmospheres are vital to the survival of life,  though they do not normally extend very far past the planet’s surface. Our atmosphere is about as thick to the Earth and the thickness of a piece of paper is to a globe.

Mercury, the smallest and lightest planet and nearest to the Sun, has virtually no atmosphere. This means that the stars would be visible through the daytime. With a lack of a serious atmosphere, Mercury is unable to retain its heat, despite its close proximity to the Sun. Unfortunately for Mercury, the planet is vulnerable to heavy cratering and has the appearance of our Moon. Mercury’s days are longer than its year, leading to extreme temperature fluctuations.

Venus is the next terrestrial world, similar in size to the Earth. It is one of the brightest objects in our Solar System, known as the morning and evening star. Its atmospheric pressure is 92 times higher than Earth and Venus’s hellish Greenhouse effect has created a wasteland. Despite not being the closest planet to the Sun, Venus has heated itself beyond belief. Venus serves as a stark reminder of the destructive power of the greenhouse effect.

Our home, Earth, is the largest terrestrial planet and has a powerful ozone layer to protect us from dangerous light and has temperatures that tolerate life and allow for liquid water. Its combination of water and CO2 provide a greenhouse effect that is just strong enough to keep our planet warm. Unlike the other terrestrials, the Earth’s surface is rich and diverse. It also has a Moon that is oddly large in comparison to the size of the Earth.

Mars is the second smallest planet and fourth terrestrial from the Sun. Its mass is just one-tenth of Earth’s. Its atmosphere is incredibly thin and exposes the planet to harmful radiation. It has polar ice caps at its poles, made from frozen CO2 and is the only world that might have once supported life. Its surface also experiences violent dust storms that can last for months, blocking the planet’s surface from view.

Examining the differences between the terrestrial planets’ atmospheres is just another reason why we are so lucky living on Earth. A perfect balance between the scorching Venus atmosphere and Mercury’s lack of one, the Earth provides the perfect home for life.

Sources: Cosmic Perspective: (195-198, 271-272), Planetary Atmospheres Article


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The Voyagers

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Image of The Voyager 2 

The study of astronomy has been made easier and easier day by day because of the powerful man-made space probes.  Two spacecrafts that I find very interesting is from the Voyager Program, called Voyager 2. Voyager 1 and Voyager 2 were two of the human-made most distant objects, other than Pioneer 10 and Pioneer 11.

But why am I more interested in Voyager 2 than Voyager 1? Well, contrary to what they were named of, Voyager 2 was the first one to be launched in 1977 to further the studies of our vast Solar System. Voyager 2 was launched on 20th August (it’s my birthday yay!) weighing about 773 kilograms where 150 kilograms are scientific instruments. Voyager 1 was named so even though it was launched 16 days after its twin is because its trajectory follows a quicker path to Saturn and Jupiter. So, Voyager 1 reached Saturn and Jupiter before Voyager 2 did, hence the name! Despite that it is 4 months to late to reach planets Saturn and Jupiter, Voyager 2 was considered more special (at least by me haha). This is because it is the only and only spacecraft that has ever reached Uranus and Neptune! Up until today, this spacecraft has served us a vast range of knowledges about the outer space that we could not be thankful enough.

Here are some of the images captured by the Voyagers

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One of the 33,000 pictures of Jupiter taken by the Voyagers
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Saturn in ultraviolet, violet and green filters captured by Voyager 2.

Read more about Saturn findings here and Jupiter findings here by the Voyagers.


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Dating Everyday Objects?

Radiometric dating is generally used for items in our solar system that exponentially older than humans. The composition of an object is evaluated for its ratio of parent and daughter isotopes. This ratio will provide a good estimate of an object’s age if we know the corresponding half-life. But can we use this same process to figure out the ages of items on a much smaller scale? Do isotopes exist, that are found naturally, that would be able to determine the ages of items that could otherwise be calculated through observation across our lifetime?

This image shows a visual representation of what the half-life of an element means and looks like across the parent isotope’s lifetime.

After browsing through several sources, it seemed that this Wikipedia page had the most plentiful information about a variety of isotopes. While many of the synthetic elements (95-118) have half-lives within my timescale of interest, they do not occur naturally, so I did not heavily investigate them. After spending some time with an abundance of tabs open on my browser comparing a handful of isotopes from familiar elements, I came to a few conclusions. There aren’t a whole lot of natural isotopes that would be useful for short-term radiometric dating. In general, there are very few isotopes that have half-lives that are 0-100 years. Furthermore, most of these isotopes only occur within artificial settings.
I’m a little disappointed by these findings, but I suppose it’s for the best that we don’t have highly unstable isotopes occurring in abundance. Likewise, the good news is that we always have the alternative methods for determining the ages of things that exist within the span of our lifetimes.


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Earth vs. Theia! First and Last Round!

I have a thing for stuff that is outrageous, different and intriguing. Greek Gods, bizarre happenings in space, and archaic events? Yes, please! So, I just recently learned about how Moon was the result of an ancient collision between old Earth (or some people call it Gaia) and another theoretical planet named Theia 4.5 billion years ago. Also known as The Big Splash or The Theia Impact, the historical collision was believed to be the origin of Moon.

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Simulation of how Theia (black), orbiting in Langrange point L4 before it collided head-on with Earth (blue) before the remnants condensed into Moon (gray) SOURCE

Theia, a hypothesized planetary-mass planet was said to be the size of Mars. In the early Solar System, Theia was an asteroid, also called Earth trojan, orbiting in Langrange points L4 and L5. Based on the investigation, astronomers think that the collision happened before our Solar System was formed, approximately 100 million years before. It was said that Theia had struck a nearly full formed Earth at a 45 degrees angle with a strapping side swipe, with an impactor velocity of 4m/s which is quite relatively slow. There is also a hypothesis which says that the impact initiated a vigorous mixing which made Theia’s iron core to mix into Earth’s core and Theia’s mantle assembled into Earth’s.

Due to the impact, shock wave spread out and materials from both planets were jumbled together and discharged out into the orbit. The materials, consisting of rocks and minerals orbit around the Earth for some time before they fused together, forming the Moon we know today.

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The artist’s depiction of the collision. SOURCE

One of the evidences which support this event was the similarities in the oxygen isotopes of both Earth and Moon. Edward Young, a geochemistry professor at UCLA and also the one who lead the study, found that the oxygen isotopes that were found on Earth and Moon are indistinguishable. This furthermore support the argument that Theia had thoroughy mixed into Earth before their debris coalesced to form Moon. Further read can be done here.

More investigations are still being made, and many hypothesis are still being voiced out by astronomers. The verdict? I myself am still not sure. Whatever it is, I believe that everything has their own existence.

 

 

 

 


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Planet Past Pluto?

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In the image above, the red oval represents the suggested path of an elusive planet called Planet X. Astronomers have been observing the orbits of objects in our Solar System and have decided there’s a strong possibility a ninth planet, almost the size of Neptune, is orbiting our Sun. Although Planet X has yet to be detected with any telescope, astronomers believe its orbit interacts with the orbits of other icy objects in the far reaches of our Solar System. In fact, there is only a 1 in 15,000 chance that the orbits of these icy objects would line up the way they do without the existence of a ninth planet. Planet X would be orbiting anywhere from 600 to 1,200 AU in its very elliptical orbit, and would take about 15,000 years to make one trip around the Sun. Astronomers are working on detecting Planet X with the help of the Keck and Subaru telescopes in Hawaii and are confident they will be able to detect it within the next five years or so.

 

SCIENCE Article


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Mission to Europa

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NASA has plans to launch a satellite headed to Europa! The Europa Clipper is planned to complete 45 flybys around Europa at varying heights above the surface (16 miles to 1,700 miles) and collect crucial data about Jupiter’s large moon. Scientists are hoping to gather information about the planet’s icy crust, its depth, and what lies underneath; astronomers are fairly certain that an ocean exists under the thick ice. Nine scientific instruments will be aboard this satellite and will measure the planet’s magnetic field (to determine size and salinity of the underground ocean), temperature, and composition. These characteristics will hopefully help astronomers and scientists weigh the possibility of life existing somewhere on Europa. These findings will also help astronomers make the decision of what comes next? If the satellite discovers a habitat conducive to living organisms, NASA may want to start planning for another trip to Europa; this time, to drill into the icy surface and make observations about the watery depths.

NASA Europa Clipper Mission

Europa Video


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Diamond Rain?

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Scientists are exploring the idea that diamonds rain down from the skies on Saturn and Jupiter. Methane exists in abundance in the atmospheres of these planets, and lighting storms turn this methane into soot (which is pure carbon). As the soot falls toward the planet’s surface, it hardens under intense pressures and forms small diamonds about one centimeter wide. These are not cut diamonds, of course, so the sky wouldn’t be glimmering like in the photo above, but the size of the stones are still impressive. Dr. Kevin Baines of the University of Wisconsin-Madison theorizes that about 1,000 tons of diamonds are rained down onto the surface of Saturn every year. As the diamonds fall from the atmosphere (over two and a half spans of the Earth), the diamonds are exposed to such high temperatures and pressures, they turn to liquid carbon. In contrast, other planets that allow for the possibility of diamond rain like Uranus, would be able to maintain the diamonds in solid form; their surface temperatures are much lower than Saturn and Jupiter’s. BBC “Diamond Rain Falls on Saturn and Jupiter”


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The Voyager Golden Record

 

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The Voyager Golden Record (Source)

The Voyager Golden Record was a disc of sounds and images included with both Voyager 1 and Voyager 2, both designed to study Jupiter and Saturn. Voyager 2 went on to study Uranus and Neptune, and is the only spacecraft to have visited them. However, these spacecraft are still gathering and emitting data even today. Recently, Voyager 1 left what is formally known as the “solar system” and is in interstellar space. Both will continue to operate until around 2025 when they run out of power. Although these were designed to observe the giants, they have another purpose: to leave a fossil of human civilization. On both Voyager 1 and Voyager 2, a golden record with sounds and images was included with the scientific instruments. This record included spoken greetings from over 50 languages, several “sounds of earth”, and music from all over the world. The music section includes famous songs such as “Beethoven’s 5th symphony” and”Johnny B. Goode” by Chuck Berry, as well as traditional songs from countries such as Peru and New Guinea. The famous astrophysicist Carl Sagan, who led the committee responsible for choosing the sounds and music, wanted to include The Beatles’ song “Here Comes the Sun” (a personal favorite of mine), and while The Beatles were okay with it, the record company EMI was not. Also included was over 100 images, including scenes from Earth and information on things like our numbering system and how to locate our solar system. These were all placed onto the two spacecraft so that if an alien civilization were to find them, they could learn about our culture. Do you think it was a good idea to send out the record with the probes? If you were to send out the record today, what would you put on it?


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Super-Earth(s)?

The idea of discovering new “Earth-like” planets has always intrigue me! I mean, they could be habitable planets that we can ACTUALLY live in? Just like in Terra Nova (I’ll explain more about that series in the end of this post!). Super-Earth, in short, means exoplanets in which their masses are higher than Earth’s, extra points if they are in habitable zones! For now, I am just going to focus on one habitable zone which is Kepler-62. Before that, hats off to those who guess why the zone’s name is Kepler! KEPLER is the name of NASA’s spacecraft in which its job is to find Earth-size planets orbiting another star AND it is also named after Johannes Kepler, world’s renowned astronomer.

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The illustration shows Kepler-62f (in front) and Kepler-62e (the twinkle on the right) orbiting Kepler-62 star. SOURCE

Kepler-62 is the name of a star in Lyra constellation (somewhat cooler than our Sun). It is the smallest habitable zone found and hosted about five exoplanets. There are two main planets in Kepler-62 zone which are Kepler-62e and Kepler-62f.

Most likely to be a water world, Kepler-62e is an exoplanet with 1.6 times the size of Earth. It orbits the red dwarf star once every 122 days. The planet is roughly 1200 light years from Earth and is believed to be more gaseous than rocky, thus called mini-Neptune. Another exoplanet orbiting the same Kepler-62 is called Kepler-62f. This planet is a bit farther out compared to Kepler-62e, seeing as its orbital period is 267 days. It is 1.4 times bigger than Earth and its equilibrium temperature is close to Mars’. Through estimation of its mass, Kepler-62f is most likely to be a rocky planet.

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The Kepler-62 system with its habitable zone in compared to our Solar System. Only two planets are in the zone which are Kepler-62e and Kepler-62f. SOURCE

After further research, it was found that both of the planets are similar to Earth but slightly bigger. It was also discovered that both planets are likely dominated with ocean. Any chances that there are life on those planets? Follow-ups exploration and research are being done to find out more about the habitable zones and other exoplanets. Are there any more habitable zones out there? YES. In fact, there was another zone found in 2013 and was named Kepler-69 and there are actually many more out there!

Now, there is one TV show that I would recommend you guys to watch. Titled Terra Nova, it tells us about the life of a family in far future, where Earth is no longer fit for living due to overpopulation and declining air quality. So, they have to move to another world called Terra Nova where in that world, it was as if Earth was pulled back to the past (means dinosaur still exist!) and they have to fight to survive. Quite a good series, seeing that I am into science fiction. Give it a chance, if you have some time! (It’s on Netflix, btw)

 


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Life: A Love Story

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Cover Photo courtesy of NASA. 

Sitting in my late-night astronomy lab last night, we watched a computer simulation (based completely on real, observed data) take us out as far into the universe as our understanding has gone. Starting in the Himalayas, Tibet, then Planet Earth, and rapidly, sooner than I thought possible, we were so far out of my realm of understanding, it made my heart race.

There is no way that I can look out at the tiny speck of dust which the Earth is, and the even tinier speck of dust upon it which our little school is, and think that we are special. Can it be coincidental, the collision of all the right materials, mixed with the right distance from the sun, the right temperature? The more we advance technologically, the easier it becomes to see across the dark void that is our Milky Way, our universe. And the more we see, the more we know, reading the spectra of other planets orbiting other stars, knowing that as we are made up of star stuff, our neighbors are as well. And our neighbors looking back at us, they too will see the fingerprint of our society’s addiction to fossil fuels and the burning of hydrocarbons. Will they look at us, millions of years more advanced, living sustainably perhaps, and see a glimpse into their own past? Could the evolution which turned us into who we are, have turned them into something else? We are looking out into the haystack as a needle, looking for another, who may or may not be looking for us too.


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