Craters

Guiding Question: What are the factors that affect the appearance of impact craters? How do scientists use craters t tell the relative age of them?

Hypothesis: My hypothesis is that the depth of the crater will be bigger and bigger, the further distance a meteorite is thrown from. I think this because when the meteor is coming down to Earth from a larger distance, it has more inertia, and therefore it gows faster. In my opinion, if a meteroite goes faster, when it comes to the atmosphere it will burn more, creating more ejecta, and melting more ground when it hits the Earth. I am not sure how scientists tell the age of craters, but I am guessing that they can use the ejecta, to see how old it is, etc. They could also observe the crater itself and tell it's relative age by seeing how much of an erosion happened over time. As for the actual appearance of craters, I believe that the factors that can influence this are the heat of the meteroite hitting, as well as it's size, shape, and speed.



Materials:
What you need in order to successfully finish this lab are safety goggles, so that you do not damage your eyes from the flour, a tray, flour (you could also use soil or corn meal), noteboo to record your observations, a spoon, small marbles (if you want, you could conduct the lab with bigger marbles, as well), and Excel to make graphs of your results.

Data + Data Analysis:
Below you can find some of the data/information that me and my lab partners collected, as well as four graphs of the results.

Graphs...

The analysis of data:

I think that my hypothesis is partially correct with the data, but there are quite a few things that I didn't address in the hypothesis, that I will address now. In the data, I realize that the diameter doesn't change as drastically as the depth of the crater (it is always somewhere around 2 cntimeters). In my opinion, the diameter of a metroite will always be the same, no matter from which how far it has hit the Earth or moon. The distance doesn't change size of the meteorite. I think that in our case, the diameter got a bit larger every time, because of the ejecta around it, that  made the diameter look larger. As for the depth of the crater, I think that I was correct, because, when the meteor is hitting the Earth, moon or any other planet in the universe from a large distance, it goes faster, because inertia has a greater impact on it. Therefore, when it comes down crashing with great speed, the depth of the crater, as well as the amount of matter melted will be larger.

Also, despite the depth becoming bigger, the amount of ejecta becoming larger as well, as the meteorite came from a bigger distance. That is because meteorite have a lot of impact on the surface of the planet they are hitting into, as they erode into it, and the matter that is eroded gets thrown all around the crater.

Conclusion:

In cocnlusion, I can say that there are several factors that affect the appearance of impact craters. One of them is speed. The faster the meteor is going, the bigger the damage on the planet it will cause. As I mentioned above this is because the further the meteor is coming from, the greater it's speed it. Speed is another factor that affects the appearance of craters. The faster the meteor is going, the deeper the crater will be, because the meteor will crash into the surface with more force. Shape of the meteor is also a factor that can influence the look of the crater. Depending on the shape, as well as the size of the meteor, the crater will be bigger or smaller, and the length as well as the shape of the ejecta will depend on those two factors. However, you must have noticed that most of the craters we see on the moon and as well as the Earth are round. This is because when the meteor goes through the atmosphere, it gets burned up, because of its massive speed, and it is mostly left falling to Earth in a rounded shape. This is also the reason why there are more craters on the moon then on Earth. Some craters that head to Earth are not quite big enough, and get burned up by our atmosphere. However, the moon has no atmosphere whatsoever, so any size meteors can hit it's surface.

Further Inquiry:

I think that this lab was quite straight forward, but still there was a few spaces where we could have potentially made an error. Firstly, as I mentioned above, we could have made an error when measuring the diameter of the crater, because of all the ejecta that was around it, the higher distance we threw the marble from. Also, we could have made a mistake by not being very accurate when throwing the marble from the distance we were supposed to. This would have made the lab/experiment unfair.

**As far as I know this is my last blog post in the school year of 2010/2011 for science, and I would really like to thank Mrs. M for teaching us so much this year, and I really feel that I have learned a lot. :)

Black holes spin faster and faster (current event)

Two scientists/astronomers from the United Kingdom have done a lot of research, by exploring huge black holes in the middle of galaxies close to our own, Milky Way. They found out that the black holes are, on average, spnning much faster than they did before. Scientists were able to notice this by using the latest technology, as well as X-ray, optical, and radio data. Astronomers also believe that almost every galaxy has a black hole in the center. Those black holes are supermassive, as they contain millions of suns. Black holes are extremely hot, and emit radiation such as gamma and X-rays. This radiation can be detected by space telscopes that were brought into space by NASA. As well as radiation, black holes area ssociated with what we call twin jets, and those twin jets are believed to be affected by the black holes' accretion disk, or the matter that swirls around the black hole.
It is believed that the spins of the black holes are very important, but scientists did not yet figure out their evolution, as well as why they are becoming faster over time.
By observing the black holes, scientists were able to get info about the population or number of black holes, and reduce the spread of the immense power of the jets. Then, by making an accurate estimate of how fast matter is acquired by the black holes, astronomers can use a number of physically-based equations to calculate how fast they are spinning.
In the past, the Universe wasn't as big as it is today, it was onlt half of it's size today, and it is believed that back then the black holes didn't have a fast spin, but as the universe continued to grow and expand, the black holes began to get faster and faster. This means that the black holes are spinning at an alarming rate, faster then ever before!
This is the first time that scientists are actually proposing a hypothesis for the evolution of black holes. Some astronomers have also suggested that the black holes that are actually swollowing light, and other matter will spin with much less speed, then the ones joining with other black holes.
With the knowledge that they gained about black holes, scientists have also started proposing more hypotheses about how some of the black holes are formed. Their results suggest that black holes somehow spun up by themselves, by joining with some other existing black holes of same or similar mass. The result of this is a faster spinning black hole.

**info from http://www.sciencedaily.com/releases/2011/05/110523074954.htm

Eclipses...

Why do eclipses occur?

The alligment of the Earth, sun and moon causes an eclipse. The two types of eclipses are solar eclipses and lunar eclipses. Lunar eclipses are the ones that happen more often. They happen when the Earth is directly between the sun and the moon. When the moon passes the Earth's shadow, a lunar eclipse happens. A solar eclipse happens when the moon comes directly between the sun and the Earth. For a short period of time, the moon blocks our view of the sun. If you are standing directly in the moon's shadow, or in the umbra, you are experiencing a total eclipse. However, you can also experience a partial eclipse, if you are in the penumbra.





What did ancient people used to think the eclipse was? 

Eclipses were interpreted differently in the ancient times by different people, when humanity didn't have the machinery and the technology to find out the scientific reasons for why eclipses occur. In some places, eclipses were viewed as evil omens. For example, when the Athenians were planning to abandon Syracuse, they couldn't, because a lunar eclipse scared them immensely. This led to their defeat by the Syracusans.  In the Chinese culture, people believed a ruthless snake attacked their sun. However, some people didn't fear the eclipses. People who built the Stonehenge probably looked at eclipses as a natural phenomenon, and did calculations of both solar and lunar eclipses.



Which type of eclipse occurs most often?  Why?  Are eclipses seen from every point on Earth?

The eclipse that happens more often is the lunar eclipse, and the lunar eclipse can be seen by everyone on the night side of the Earth, while the solar eclipses can only be seen if you are standing in the umbra or penumbra of the eclipse. Solar eclipses are VERY rare, they only happen every6 months or so.

The next eclipse is predicted to happen on June 1st, and it will be a partial solar eclipse.

Now, you may wonder how you should observe an eclipse, and if they are dangerous. Yes, eclipses are dangerous for a few reasons. Firstly, you should never look directly at the sun, because your eyes could be severely damaged from the UV rays. The sun's rays are very strong and in very severe cases, if you look at an aclipse for too long you can lose your eyesight. Below you can find a safe way to look at an eclipse, and you can make the pinhole projector yourself!

WARNING!

Permanent eye damage can result from looking at the disk of the Sun directly, or through a camera viewfinder, or with binoculars or a telescope even when only a thin crescent of the Sun or Baily's Beads remain. The 1 percent of the Sun's surface still visible is about 10,000 times brighter than the full moon. Staring at the Sun under such circumstances is like using a magnifying glass to focus sunlight onto tinder. The retina is delicate and irreplaceable. There is little or nothing a retinal surgeon will be able to do to help you. Never look at the Sun outside of the total phase of an eclipse unless you have adequate eye protection.

Once the Sun is entirely eclipsed, however, its bright surface is hidden from view and it is completely safe to look directly at the totally eclipsed Sun without any filters. In fact, it is one of the greatest sights in nature.

There are five basic ways to observe the partial phases of a solar eclipse without damage to your eyes. We will describe each of them below. We'll also explain how to safely watch an eclipse with binoculars or a telescope.

The Pinhole Projection Method

One safe way of enjoying the Sun during a partial eclipse--or anytime--is a "pinhole camera," which allows you to view a projected image of the Sun. There are fancy pinhole cameras you can make out of cardboard boxes, but a perfectly adequate (and portable) version can be made out of two thin but stiff pieces of white cardboard. Punch a small clean pinhole in one piece of cardboard and let the sunlight fall through that hole onto the second piece of cardboard, which serves as a screen, held below it. An inverted image of the Sun is formed. To make the image larger, move the screen farther from the pinhole. To make the image brighter, move the screen closer to the pinhole. Do not make the pinhole wide or you will only have a shaft of sunlight rather than an image of the crescent Sun. Remember, this instrument is used with your back to the Sun. The sunlight passes over your shoulder, through the pinhole, and forms an image on the cardboard screen beneath it. Do not look through the pinhole at the Sun.

Solar Filters

A second technique for viewing the Sun safely is by looking at it directly through a specially designed solar filter. Such filters permit only a miniscule fraction of the Sun's light to pass through them. Advertisements for solar filters may be found in popular astronomy magazines.

**info from http://www.mreclipse.com/Totality/TotalityCh11.html Check it out if you want to learn more!