In Other News: We Can Analyze Atmospheres of Super-Earths

Posted on February 16, 2016 by andyastronomer

(Feature Image courtesy of ESA/Hubble, M. Kornmesser)

In the past week, the big news in astronomy was the first detection of gravitational waves, a phenomenon predicted by Albert Einstein in his general theory of relativity. No doubt within a few years students will be reading in textbooks about how the LIGO experiment measured the gravitational waves created from a collision of two black holes.

However, beneath the incredible news of LIGO’s success is another astronomical milestone. Just today, a team from University College London (UCL) was able to observe the atmosphere of a “super-Earth” for the first time. In short, super-Earths are planets larger than Earth and smaller than the gas giants of our Solar System. This class of planets is thought to be the most common in the Milky Way Galaxy, and therefore, our search for life on other planets has focused largely on extrasolar super-Earths.

Measuring Extrasolar Atmosphere

Using a new form of analysis, The UCL team was able to take Hubble data and determine the atmospheric structure of 55 Cancri e, an extrasolar planet about 40 light years away. An excerpt from the UCL article describes the analysis technique in more detail:

Observations were made by scanning WFC3 [Wide Field Camera 3] very quickly across the star to create a number of spectra.  By combining these observations and processing through computer analytic ‘pipeline’ software, the researchers were able to retrieve the spectral fingerprints of 55 Cancri e embedded in the starlight.

As far as I can tell, the astrophysicists at UCL were able to analyze the atmosphere of a planet 40 light years away by setting the Hubble’s cameras to “burst mode.” Incredible!

What We Learned About 55 Cancri e

(Video courtesy of HubbleESA – The European Space Agency)

The analysis run by UCL found that the atmosphere is largely composed of Hydrogen and Helium, suggesting that the planet retained a lot of the material from the initial nebula that birthed the planet. Also interesting is the presence of Hydrogen Cyanide in the atmosphere, a chemical that is often an indicator for a carbon-rich atmosphere.

However, considering the average temperature of 55 Cancri e is about 3,600° F, even if we were to filter out the incredibly poisonous Hydrogen Cyanide from the atmosphere, we would probably find the planet a bit too toasty. In addition to obscenely hot temperatures and toxic gas, we would have to get used to the 18 hour year of 55 Cancri e. Yes, 55 Cancri e makes a full orbit around its star (55 Cancri) every 18 hours. Perhaps the planet’s small distance from its parent star explains those hot temperatures…

For all of the downsides to paying this planet a visit, there is one fantastic upside. The planet is known as “The Diamond Planet” because much of the carbon that forms the planet is in diamond form. Maybe some day, when we can travel light years at a time and land on planets with temperatures in the thousands of degree Fahrenheit, we will be able to stand on a planet made of diamonds.

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Courtesy of Yale (image by Haven Giguere)

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Blog #4

Posted on February 16, 2016 by astronomer0110

A topic I’ve always found interesting is the idea of the likelihood of extraterrestrial life in the universe. Many scientists in recent history have noted that there is an extremely high probability of life elsewhere in the universe due to the immense amount of stars and planets that must exist with favorable circumstances for the development of life. The Drake Equation is a famous idea that basically predicted that there should be many examples of extraterrestrial life based upon a number of parameters. However, we haven’t observed any other life directly or received any signals from it. There are a few possible explanations for this. We might truly be alone in the universe, other forms of life might be too far away to send signals, or these other civilizations destroyed themselves. Possibly, life originated from organic molecules on other planets but never got the chance to develop as fully as our life did on earth. A contrasting idea is the rare earth hypothesis, which states that earth fulfilled so many requirements of advanced life so perfectly that it would be unlikely for that to be duplicated anywhere else. Something that I’m fascinated by is the relationship that religious belief has to the idea of extraterrestrial life. Most people who believe in God or a religion would probably say that the earth and the development of humanity is unique, and (for now), there’s nothing to prove them wrong. If we ever discover another form of extraterrestrial life not explained in the Bible or other religious documents, it would possibly damage the credibility of a lot of religions. Personally, I think the fact that earth was so perfect and the fact that we have never even found a trace of other intelligent life seems suspicious–especially considering that humans developed consciousness and advanced thought at such a crazy level. The picture below shows some ideas about the rare earth hypothesis (Rare earth)Earth-factors


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Tides can be Fun(dy)

Posted on February 16, 2016 by Gabi Grys
Bay of Fundy
The Hopewell Rocks in the Bay of Fundy

Anyone who has spent the day at the beach has experienced the changes of the tides. Few of us, however, have ever seen anything like the Bay of Fundy, a body of water between New Brunswick and Nova Scotia in Canada with the largest tidal range in the world. Within twelve hours between low and high tides, the bay can rise and fall up to 53 feet.

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With such a drastic change in tide, entire landscapes can appear and disappear in a day like. 

What causes such a significant change in the tides? The strength of the gravitational attraction between the Moon and the Earth changes depending on location (whether a place is on the “far” or “near” side of the Earth) because distance impacts the force of gravity. This difference causes two tidal “bulges” which the Earth rotates through as it spins on its axis throughout the day. This leads to high and low tides. The Bay of Fundy’s high tides are particularly high because of the natural resonance of the water and the unique shape of the bay. 

If you’re looking to find the most drastic changes, here’s a map of the 170 mile coastal line of the bay with average tide heights at high tide:

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Gravity is Working Against Me

Posted on February 16, 2016 by Sofia

 

Gravity is arguably the most important aspect of our study of the universe and our solar system. Isaac Newton, famous for his three laws of motion, determined that the force of gravity could be expressed mathematically. This led him to create his universal law of gravitation. His law contains three key statements about the force of gravity. The first is that every mass attracts every other mass in the universe through the force of gravity. Secondly, he postulated that the strength of the gravitational force attracting any two objects is directly proportional to the product of their masses. Finally, he stated that the strength of gravity between two objects decreases with the square of the distance between them. His equation rests on the gravitational constant that is multiplied by the relationships listed above. The constant has been measured to be 6.67 x 10^-11 m^3/(kg x sec^2).

Isaac Newton.jpg
Anglotopia

Newton’s law is not only applicable on its own, but can also help expand the knowledge of the universe we obtained from Kepler’s laws. In conjunction with Kepler’s laws, astronomers now know that planets are not the only objects with elliptical orbits. Newton’s law illustrates that any two objects going around one another will follow an elliptical pattern of motion. Newton’s law also shows that the objects in orbit will move around their common center of mass when in the orbits Kepler discussed. Finally, Newton’s law illustrates that the orbits Kepler postulated could be both bound and unbound. Newton’s law expanded on Kepler’s discussion of speed in relation to distance and showed that the notion is true even with parabolic and hyperbolic orbits. It is important to understand the interplay between the law of gravitation and the laws of planetary motion to understand how all of the object in the universe move, not just the planets in our solar system.


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Why do we have tides?

Posted on February 16, 2016 by nedastro2110

Today I want to talk about tides! Above is this video of Clovelly, England and the drastic tide that they experience day in and day out, especially when it is spring tide, meaning the moon and sun’s tidal forces line up to create even more drastic tidal forces. What is amazing about that video is how the entire harbor empties during Spring tide and it’s actually completely a result of the sun and moon, objects that are thousands of kilometers away from us! Now what is actually causing these tides? Well it’s caused by the gravitational forces between Earth and the Sun and Moon. Essentially the gravitational force is different across the earth as the side closest to the moon and/or sun has a stronger attraction compared to the far side. Therefore, the difference between the attraction on opposite sides of the earth create what is known as a tidal force. This tidal force is essentially a stretching force that pulls the earth in the direction of the moon or sun. This is illustrated in the image below.

 

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NOAA

 

We witness this tidal force most in the oceans because liquid is most easily affected by gravitational forces but the land moves as well, only a couple centimeters during spring tide, but still it moves! The entire sphere of the early is being stretched towards the moon or sun. Now, because of the distance to the moon, it has about double the effect on tidal forces the sun has but when they work in combination, which is known as spring tide, the force is strong enough to empty the harbor at Clovelly at low tide and be almost overflowing at high tide. This drastic distance is created by gravitational forces from objects hundreds of thousands of kilometers away. That’s pretty cool if I do say so myself.


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The Martian — Could It Really Happen?

Posted on February 16, 2016 by clharrell

97-front

Matt Damon’s critically acclaimed film “The Martian” broke records and set a new standard for space exploration movies. The film was even praised for its scientific accuracy by Neil DeGrasse Tyson. While most of what occurs in the film is theoretically possible, a few things stand out to be implausible. The first question I had when I saw the movie regarded the dust storm that caused the whole meltdown. The storm itself is certainly possible – however the questions lie in the effects the storm have on the crew and their lander. Mars’ incredibly thin atmosphere would hinder the wind’s ability to apply large forces to the lander.

The most surprising thing I found out while researching this topic was the feasibility of growing plants in martian soil. I found myself discounting the idea as impossible while watching the film but was surprised to learn that the soil has a suitable chemical composition for growing plants. Lastly, Matt Damon seemed to move in a similar manner to us on Earth. This is likely an adaptation to make filming easier, due to the fact that Mars has 30% of the gravity that Earth has.

image source


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Mayan Astronomy

Posted on February 16, 2016 by andyastronomer

 

At the end of 2012, the whole world was abuzz with the news that on December 21st, the Mayan calendar would end. Some claimed this ominous event signaled the end of the world, while others simply suggested the Mayans would have likely extended their calendar if they were still around.

Who Did It Better: Ptolemy or the Mayans?

In any case, a large part of the Mayan legacy is the astounding precision with which they measured the movements of the heavens. Michael John Finley compared the calculations of the Maya and those of Ptolemy to our modern measurements:

Mayan_Calculation_Comparison
Courtesy of Michael John Finley

Although we are splitting hairs when comparing the Mayan and Greek measurements, the Maya were able to make more accurate calculations for the Lunar month, Synodic period of Venus, and the Solar year.

The Significance of Astronomy for the Mayans

For the Mayans, observation of the sky was much more than a scientific exercise. The Mayans saw the Sun and planets as gods tracing out their path in night sky, and the movement, position, and alignment of celestial bodies heavily affected the actions of the Mayan people. For example, Venus corresponded to the god of war in Mayan culture (compared to Mars in the Greek/Roman culture), and the Mayans saw the rise of Venus in the morning sky as a sign of good fortune in wartime pursuits. Consequently, Mayan rulers would rely on ancient astronomical predictions of when Venus would rise in the morning sky in order to plan military campaigns.

The Dresden Codex: A Link To The Past

Dresden_Codex_2-min.jpg
Courtesy of WikiMedia

When the Spaniards conquered much of modern-day Latin America, they were appalled by the ritual and spiritual practices of the indigenous people groups. As a result, they burned most of the written texts produced by the cultures of Latin America. Fortunately, a few key texts survived, including the Dresden Codex. The text was brought back to Europe as an example of native art, and was re-discovered in the 19th century when a director for the Dresden Public Library in Germany purchased the piece from a private owner (hence the name).

The codex can be best described as a priestly handbook, but much of the information in this text is astronomical data. The book contains almanacs, eclipse tables and data on the timing of planetary positions. This text, among other archeological discoveries, has given us a lot of the knowledge we have today on Mayan culture.

Most interestingly, the Dresden Codex further emphasizes how inextricably linked scientific and religious practice were in the Mayan culture. The Maya observed the sky for centuries if not millennia, and they did so because they believed they were not just observing stars and planets. They believed they were observing the gods themselves. And although we may not share their belief, perhaps it is a similar sense of wonder that moves us to study the heavens today.


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Blog #3

Posted on February 16, 2016 by astronomer0110

For this week’s blog, I’ve decided to talk a little bit about the intuition behind the idea of  gravity. I find this theory really interesting because it makes so much sense when you think about it. As history moved along, Einstein and other physicists managed to explain the reasons why gravity acts upon objects. Gravity is due to the fact that objects with heavy mass pull other objects towards them with a gravitational force. These gravitational forces can be described by the equation Fg=(GM1M2)/d^2. For example, people are pulled towards the earth and the earth is pulled towards the sun in such a way that it continually orbits around it. According to Einstein’s theory of general relativity, very massive objects like the sun can push “down” on the fabric of spacetime and distort it, which causes planets to orbit around it. In class, we saw this in a demonstration where larger spherical objects pushed down on the fabric and caused smaller spheres to “orbit” around them. I find it interesting that Newton and other scientists knew how gravity worked for many centuries before we discovered why exactly it actually did work. I think that this idea relates to a more general point about science as a whole. The beauty, simplicity, and intuitive nature of the laws of physics and mechanics that govern the universe are astonishing. The fact that we can determine the behavior of objects at any place in the universe and realize why they are moving in such a way says something about the capacities of the human brain and the amazing nature of our universe as a whole.  Other fields like chemistry and even biology also follow patterns that apply across many systems and can be explained in really interesting ways. That, for me, is what makes science such an interesting subject to learn about. There is definitely a feeling of satisfaction that comes from understanding why things work, and that’s because humans are meant to constantly expand our understanding of the universe. The picture below demonstrates the intuition behind the moon’s orbit around earth (Moon orbit).

space-time


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Near, Far, Wherever You Are

Posted on February 16, 2016 by Sofia

Understanding the ability of objects in the sky to change their spectra is vital to understanding the universe we live in. In order to fully understand the motion of the objects in the universe, we can use their spectra to see changes in their light emissions. The spectra of objects show the types of visible light the objects are emitting and thus the wavelengths of their light as well.

redshift:blueshift
Science Questions with Surprising Answers

We can use the changes in their wavelengths to understand their motion in the sky. When objects are moving away from us, their spectral lines will move toward the red colors. This illustrates that the light emissions are moving to longer wavelengths and thus losing energy as they move away from us. When objects are moving toward us, the light emitted will move toward the blue end of the visible light spectrum. Because the wavelengths are becoming shorter, blueshifted objects gain energy as they move toward us. Another important consideration when looking at spectra is the extent to which the lines move. The distance they travel along the spectrum highlights the speed at which the object is moving toward or away from us. If the object is moving quickly, the lines will shift more drastically than that of an object that is moving more slowly. It is important to remember though that the change is the important factor not the direction of the movement along the spectrum. Regardless of if it is blue or redshifting, the distance of the change is the key factor for determining speed. All in all, the spectra of objects in the sky give vital information for determining objects’ movement in the sky, and they need to be taken into account when studying the universe.


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Gravity Waves and the Graviton

Posted on February 16, 2016 by 2016spaceodyssey

So physicists have recently announced the discovery of Gravitational Waves, but what does that mean for the Graviton?  Similar to how protons and electrons carry electrical charge, it is theorized that the Graviton carries, you guessed it, gravity.  Because it is a subatomic particle it is more of a focus for particle physicists than for astrophysicists but that doesn’t mean it won’t have a significant impact in astronomy if it is ever discovered.  The discovery of the Graviton could potentially complete the Standard Model (particle physics) and give astronomers an even more accurate picture of how the universe moves and celestial objects interact.

So does the discovery of Gravitational Waves mean the Graviton has been discovered?  Unfortunately no.  The discovery of Gravitational Waves is extremely significant as further evidence supporting Einstein’s General Relativity as well as giving astronomers “ears” to observe the sky with.  But just because there is a wave doesn’t necessarily mean there is a particle that goes along with it.  Think of sound, there are sound waves but there is not a “sound particle.”  So while the discovery of Gravitational Waves is a huge breakthrough for physicists and astronomers there are still plenty of mysteries that gravity poses.

gravity-waves-3
The question remains if there exists a particle that carries gravity. Picture from Extremetech

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