Switching of Seasons


The second conceptual objective, “I can explain how planets have seasons”, relates specifically to this article. Throughout our class periods, and in section 2.2 of our cosmic perspective book,  we have discussed this concept. Although many believe that the distance between our Earth and sun is the reason for the seasons, it is actually the Earth’s tilted axis that causes the sunlight to shine on Earth at different times of the year. According to this article, the tilt of the axis is always facing in the same direction while the Earth rotates around the sun, which is also shown by a picture of the Earth and its tilted axis of 23.5 degrees. Therefore, when the Earth is on one side of the sun, the Northern Hemisphere has the sun beaming directly on it opposed to the Southern Hemisphere and vice versa. As we discussed in class in our lecture tutorial book with the section about direct light and the tilt, the article also refers to this idea. In the lecture book, we saw that the two lights (A & B) were shined upon a screen with A’s light more direct and brighter and B’s not as much. This article also uses this by stating, “Imagine the sun is a can of spray paint and the floor is the Earth’s surface. If you hold the can directly above the floor and spray, the drops will land closer together and be more vibrant. If you put the can of paint on the floor and spray from an angle, the drops will land far apart from eachother”. The article used this idea because it is an easy way of explaining how land that is closer to the poles recieve less intense rays of sunlight because it is spread across more area. Using the light idea from class and the articles explaining of the paint technique has helped me to understand objective two in a better and more creative way of understanding. I have alwasys been curious to this concept and can now say i know the meaning of why planets have seasons and will be able to explain to someone if i ever receive the question.

How the seasons shift on Mercury, Venus, and Mars

I found an interesting article on cosmosmagazine.com, titled “How the seasons shift on Mercury, Venus and Mars“, by Phil Ritchie. This article explains how Earth and its neighboring planets Mercury, Venus, and Mars have its seasons. The author stated that, “seasons are based on the orientation of a planet’s poles” (Ritchie). In class we learned that the distance from the earth to the sun does not determine the seasons; technically we are closer to the sun in the winter time. Because of Earths tilt and the direction of the sun we learned that in July the Northern Hemisphere get more direct sun light and less in the Southern Hemisphere. This axial tilt is what causes our seasonal change. The intensity of the sun and the amount of time the sun is in the sky for are directly responsible for the cause of the seasons on earth. I found this article interesting because it mentions how Mercury does not have a tilt, which makes it lack seasons, but because of its high elliptical orbit it creates a version of summer and winter.

Antarctica Telescope Benefits From Darkness

I found an interesting article on space.com titled “Extreme Astronomy Unlocks Cosmic Secrets From the South Pole.”

This article is about Antarctica’s South Pole Telescope. The telescope is mapping cosmic microwave background which is leftover energy from when the universe first expanded. By mapping out the CMB astronomers are able to tell where the largest structures in the universe are. Astronomers are also able to tell  how galaxy clusters grew in different eras of the universe, and how dark energy works. CMB is also helping to tell scientists how gravity works by measuring how large clumps of matter form over time. The South Pole’s environment is perfect for observing the universe because it has a very dry climate and water vapor from wetter climates interferes with observations.

This connects to our conceptual objective because the position of the South Pole telescope is affected by the long darkness that Antarctica experiences over its winter months, which is affected by the Earth’s seasons. During the June solstice, which equals winter in the Southern Hemisphere, Antarctica has nighttime all day long because it is at the south pole and therefore is tilted away from the sun. The Earths tilt means that the Sun will stay below the Antarctic horizon at all times and will not be visible.

I thought that this article was fairly interesting because we North Americans live in an area that is affected by light pollution to a great degree. It is good to know that astronomers have places on Earth that they can go where they can get away from light pollution and have the untouched darkness of the night sky to take observations from during a good chunk of the year. I’m sure that the fact that the South Pole telescope exists means that astronomers have been able to make some pretty great discoveries and will continue to make important discoveries so long as they have the ability to observe the Antarctican night sky uninterrupted.

The angle of tilt determines the extremity of seasons for planets in our solar system

I found that the article entitled “Why Earth has 4 seasons” from earthsky.org coincided extremely well with our second conceptual objective, “I can explain how planets have seasons.” In this article, the author, Deanna Conners, discusses how it is a common belief for many people that Earth’s changing distance from the sun causes the changes in the seasons; however, as she discusses, this is most definitely not the case. In fact, distance has nothing to do with the “reason for the seasons.” Over a year, the Earth’s tilt remains at a constant angle of 23.5 degrees relative to the plane of Earth’s orbit around the sun. Because of this, Earth’s northern axis is always pointing toward the same direction in space. Although the tilt remains the same, the relative position of our planet’s tilt with respect to the sun does change as Earth orbits the sun. This means that for one half of the year the Northern Hemisphere is facing the sun, and for the other half of the year it is facing away from the sun. Therefore, when the Northern Hemisphere is pointing toward the sun it is summer because the sun’s rays strike that specific part of Earth at a more direct angle, making that region of Earth warmer. Thus, when the Northern Hemisphere is pointing away from the sun it is winter because the sun’s rays strike that specific region of Earth in a much less direct angle, making it cooler. Other planets in the solar system are also tilted at various angles. Conners addresses that the angle of tilt determines how extreme seasons are on the planets. Uranus rotates at 97 degrees and therefore experiences extreme seasons, whereas Venus is tilted at 177.3 degrees, causing it to have very little change in seasons.

This is relevant to what we have been discussing over the past few class periods because through an initial picture comparison of the sun in January and July, and our most recent lecture tutorial, “seasons,” we found out that the Earth’s distance from the sun does not have anything to do with the seasons. We started this conceptual objective by looking at a picture of the sun in two different months as stated above. In the pictures, the sun appears closer to the Earth in January than it does in July. At first, I said that the sun’s distance from the Earth was responsible for the seasons, but these pictures proved me wrong. If distance was really responsible then the sun would be closer in July (summer), rather than in January (winter). After completing the lecture tutorial, we found out that, in all actuality, the two things most directly responsible for the cause of the seasons on Earth are as follows: 1) the intensity of the sun and 2) the amount of hours of sunlight the Earth gets, which all comes back down to the angle of Earth’s tilt.

I really enjoyed this article because not only did it clarify that the angle of the Earth’s tilt influenced the seasons rather than the distance between the sun and Earth, but it also showed that the differences in angles of other planets influences the extremity of seasons on those planets (i.e. Uranus tilted at 97 degrees which causes it to experience extreme seasons). Before beginning this conceptual objective I really did believe that the “reason for the seasons” was solely because of the distance between the sun and Earth. Although I found this concept confusing and hard to understand at first, I now know that it is much easier to understand than I had originally thought; also, it is actually extremely interesting to me that the angle of the tilt can cause either really extreme or incredibly mild seasons, and that is something I would really like to read more about in the future.

1 Billion Stars Mapped

I read an article on space.com called “1 Billion stars Mapped! Most detailed catalog of Milky way is revealed”. This 3D map is called the most detailed many of a billion stars in the Milky Way galaxy. Released on, “Sept. 14… along with a sneak peek at the brand-new data in millions of stars collected by the European Space agency’s Gaia Spacecraft”(Weiterng, 1). The spacecraft Gaia has been scanning the sky to create an image of more than a billion stars in the Milky Way since 2014. In only, “fourteen months into its five-year mission, Gaia’s data release is only the beginning of loads of new information about our galaxy that Gaia is expected to produce”(Weitering, 1). This mission will build the most comprehensive, detailed, and accurate catalog of all time. The majority of the data, “Gaia will be used not just for constructing a gigantic and unprecedented 3D map of the Milky Way, but it will also inspire new research… knowing the stars positions, movement, and other physical qualities”(Weitering, 1). When this map is finished it will help may astrometric and students figure out what  the stars are doing in the night sky.

Our conceptual objective is to be able to explain how astronomical objects appear to move in the sky. This article relates to the conceptual objective because it’s helping us show that they are still discovering new stars in the Milky Way. And is also helping us by giving us a physical map so we can learn what the stars do at night. In class we talked about asterism, and how there are many different types like, Orion Belt and the Big Dipper. These are just a few main ones we have known since the day of time. Also in class we worked in are tutorial books and talked about the rotation of the stars through the night. This 3D model will help make it easier to understand how the stars look and are moving through the year.

This article was interesting to me because they are still finding new stars.Also the spacecraft orbiting and scanning the sky called Gaia was such a successful mission. It helped me connect with the Milky Way, and how it is extremely large. There are so many stars to look at in the night sky and to think they are still finding new stars that all have their specific details is amazing. And finally I connected from this article to show me how the stars move throught the night sky.

The Stars in the Sky

I found an article from sciencedaily.com entitled, “Farthest stars in Milky Way might be ripped from another galaxy.” The article explains that the 11 farthest known stars in our galaxy are 300,000 light years away, and that 5 of those may have been “ripped” from a different galaxy called the Sagittarius Dwarf. This galaxy orbits the Milky Way, and has lost much of its mass and stars over time. Scientists have figured out that the gravitational pull of our galaxy is literally tearing the Sagittarius Dwarf apart, and so some of the stars we see in the night sky are actually supposed to belong somewhere else.

The article relates to what we’ve been talking about in class because it explains at least one small part of what we see when we look out into space from Earth. From our point of view on this planet, all the other stars, planets, and other celestial bodies appear to orbit us. However, this is simply an illusion caused by the Earth’s rotation around the sun. From our point of view, the sun and stars appear to rise in the east and set in the west. Rising and setting is an illusion caused by the horizon. When the sun sets, it is no longer visible from our point of view because it has dipped below the horizon—meaning that the Earth is blocking us from seeing it. When it rises, it is no longer blocked by the Earth and we are able to see it again. Every celestial body appears to move at the same speed because of the Earth’s rotation; therefore, if the sun rises with a particular constellation, it sets with that constellation as well.

I thought that this was an interesting, informative article because it explains where a few of the billions of stars that we see in the night sky come from. Looking up at the sky at night is fascinating because space is so mysterious and infinite and there’s still so much that we don’t know about the universe. I thought it was weird that our galaxy could damage another so severely without even trying. It’s not like our galaxy planned to do it; both galaxies simply exist near each other and by chance just happened to have a profound effect on its entire structure. It’s so strange that celestial bodies are constantly interacting with each other like that throughout the universe.

UPDATE: (PERSONAL REFLECTION) I thought that the article was interesting and meaningful because it helped to reinforce some of the things that we learned in class about how celestial bodies appear to move in the sky. It also took what we learned about stars rising and setting one step further and explained exactly where a few of those stars came from, which I thought was interesting. Regardless of how far away these stars are or where exactly they came from, however, they all appear to move at the same speed, since this movement is an illusion caused by the Earth’s rotation, and the Earth rotates at a constant rate.


Why the World does not Revolve Around You

When reading an article from space.com entitled “How Fast is the Earth Moving?,” it is discussed that when observing the stars, sun, and the planets the Earth seems to be the center of our galaxy. However, everyone by now should know that such is not the case; As taught in class, the stars and sun do appear to spin around our sky rising in the East and setting in the West, the Earth is actually spinning around the sun. As explained in the article, inconsistencies of planetary movement of Mars when Earth passes it in orbit as well as the difference in height of the sun as the seasons pass prove that the Earth is not the center of our solar system. We have learned in discussion that the sun’s height rises when it gets closer to the summer solstice and lowers when Earth approaches winter solstice, thus proving that the sun cannot orbit the still Earth and move 2 hours east if it were not the center of our galaxy. It would have the same orbit all the time, aside from the gradual movement of the galaxy. Obviously, the Earth revolves around the sun. The tilt of the axis is what causes the sun to seem like it moves up and down our sky through the year and the rotation of the Earth causes the sun to move from East to West throughout the day.

Learning about the movement of the sun, stars, and planets helped better my understanding of this natural phenomenon. While I am not completely oblivious to the sun being our center, it was nice to understand how and why it moves in such a way (and as and side note: it was nice to finally clear up its movement as east to west and not just guess and did hope for the best).

Link to article: www.space.com