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Earth Formation

One of the oldest questions for mankind is how the Earth was formed. However, no one has an exact answer. First by the best estimates it occurred over 4 billion years ago before any life appeared. So there are no eyewitness accounts and other pieces of evidence. The best we can do is look at the geologic record and the stars to get our answers. While we may not have the entire picture we have a good idea and it all starts with how stars are born.

Just like the formation of the Earth and other planets stars take a long time to be be born. Stars are essentially formed from clouds of gas in space. We know these as nebulas. You can basically consider them to be star forges. Over time gravity causes the atoms of gases and space dust to start coming together and gathering. Over time this gather of gases gains more mass and with it stronger gravity. This is a process that can take millions of years. In time the gravity causes the gases, mainly hydrogen to fuse in a nuclear reaction and a star is formed.

The formation of the Earth occurred after this intial phase happened for our Sun. After the Sun was formed we know from observations and other indirect evidence that there were left over gases and heavier elements. The gravity of the Sun helped to flatten these left overs into a disk and start to fuse them together. This created the planetesimals and planetoids which would later make up the planets. Over time these planetesimals would collide creating even bigger masses. It was in this method that the Earth was eventually formed.

Now we need to know that fusion eventually creates heavier elements such as carbon and iron. These elements were to compose a significant part of young Earth. The pressure and heat from radioactive decay of elements and the aftershocks of massive collisions caused the Earth to be molten. Over time the surface of the Earth cooled and became the Crust. However the molten layers that remained became our mantle and the core. The currents of this massive underground ocean of magma cause volcanic activity that released gases. These would lead to the creation of the atmosphere and the oceans starting the water cycle.

The formation of the Earth was only the beginning and we still see the Earth changing year by years through erosion and plate tectonics. However in learning more about the formation of the Earth we are able to better understand what makes life possible on our planet.

If you enjoyed this article there are several others on Universe Today that you will enjoy. There is a great article on plate boundaries and an interesting piece on early Earth.

You can also find some great resources online. There is a great web page on the University of Oregon web site that goes into detail about the formation of the Earth. You can also look at the Hadean page on the Smithsonian website. It talks about the Hadean period the period of geologic time when the Earth was formed.

You can also listen to Astronomy Cast. Episode 108 is about the life of the Sun.

Reference:
NASA

Posted on by Tega Jessa

What was the Largest Tornado Ever Recorded?

Determining the biggest tornado can be a tricky endeavor. First of all, there is no direct absolute way to measure the width of a tornado. There is also the fact that a tornado can be ranked by many factors such as wind speed, level of destruction caused, drop in barometric pressure, or the length of travel path. Each of these play a role in determining the overall power of a tornado.

Another problem is that in many cases like in the Tornado Alley of the Midwestern United States, a storm system often produces multiple tornadoes. This can make it difficult to measure an individual tornado since it destructive force is combined with that of other tornadoes spawned by the same storm system.

While there is no definitive method there are some records that can give us a general idea about some of the greatest tornadoes in recorded history. The most powerful tornadoes tend to be in the United States, but there are others that can compete in other parts of the world.

The title of most devastating tornado goes to the Tri-State tornado of 1925. The twister traveled through three states and killed 698 people. This makes it the deadliest tornado in US history. It also had the longest track and duration traveling a distance of over 200 miles and lasting 3.5 hours. Even then this is just for the United States. The deadliest tornado in the world occurred in 1989 in Bangladesh taking over 1300 lives.

The closest measure to the Biggest tornado would be the widest damage path. This the with of the destruction a tornado causes not it actual size. This measure is a good estimate for the actual width of the tornado’s funnel cloud. The storm that holds the record occurred in Wilber-Halland Nebraska. The tornado had a destruction path with a width of over two miles. The tornado destroyed most of the buildings in the area.

As you can see you define the largest tornado by many factors. This just shows the various ways in which we as casual observers can measure and determine the power of a tornado. This provides an interesting insight into what makes a tornado so destructive and hard to predict. It is also important to remember once again that tornadoes rarely occur as singular phenomenons. A group of smaller tornadoes in an outbreak can be as effectively powerful and destructive as one major tornado.

If you enjoyed this article there are other pieces on Universe Today that you will loved to read. There is an interesting article about the winds on Venus. There is also another interesting article on Global warming.

You can also check out resources online. There is a great article about Tornadoes on National Oceanic and Atmospheric Administration website There is another interesting piece on tornadoes on the University Corporation for Atmospheric Research website.

You can also check out Astronomy Cast. Episode 151 talks about atmospheres.

Posted on by Tega Jessa

What are Cumulonimbus Clouds?

Cumulonimbus clouds. Credit: NASA

Cumulonimbus clouds are a type of cumulus cloud associated with thunder storms and heavy precipitation. They are also a variation of nimbus or precipitation bearing clouds. They are formed beneath 20,000 ft. and are relatively close to the ground. This is why they have so much moisture. Cumulonimbus clouds are also known as thunderheads due to their unique mushroom shape.

These clouds often produce lightning in their heart. This is caused by ionized droplets in the clouds rubbing against each other. The static charge built up create lightning. Cumulonimbus clouds need warm and humid conditions to form. This gives them the moist warm updrafts needed to produce them. In some instances a Thunderhead with enough energy can develop into a supercell which can produce strong winds, flash floods, and a lot of lightning. Some can even become tornadoes given the right conditions.

Despite the heavy rainfall these clouds produce, the precipitation normally just lasts for around 20 minutes. This is because the clouds require not only a lot of energy to form but also expend a lot energy. However, there are exceptions to the rule. There are also dry thunderstorms which are cumulonimbus clouds whose precipitation does not touch the ground. This type is common in the Western United States where the land is more arid. It is often cited as a cause of wild fires.

An overlooked result of Cumulonimbus clouds are flash floods. This was proven recently in Atlanta, Georgia area of the United States. The state had gone through a two year drought and water supplies such as creeks and rivers were low. However the fall season brought with it the end of the drought and a lot of Thunderstorms. Even though Atlanta is not near any major waterways, the resulting flash floods were on a scale seen only with areas near major rivers with wide flood plains. This demonstrates how much precipitation that Cumulonimbus clouds can produce even in a short amount of time.

Cumulonimbus clouds are a perfect example of how difference in altitude can affect the formation of clouds. Cumulonimbus clouds form in the lower part of the troposphere, the layer of the atmosphere closest to the surface of the Earth. This region due to evaporation and the greenhouse effect produces alot of the warm updrafts that make creation of cumulus and cumulonimbus clouds possible. The turbulence created by the friction between air and the surface of the Earth combined with stored heat from the sun helps to drive the majority of weather.

If you enjoyed this article there are others on Universe Today that you will be sure to enjoy. There is a great article on cloud types and another on the composition of the Earth’s atmosphere.

There are also great resources online. USA today has a great article on cloud types. You can also check out the cloud types website for the University of Illinois.

You can also check out Astronomy Cast. Episode 151 is about atmospheres.

Posted on by Tega Jessa

First Rocket

Dr. Robert Goddar with on his early rockets in Roswell

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Rocketry is actually older than many people think. The first rockets originated in China and subsequently the Middle East with the discovery of gunpowder. These rockets were used for military purposes or as entertainment. The use of rockets and gunpowder would eventually transform warfare, and to this day we still use rockets in pretty much the same way they were used 700 years ago. The only difference is that when we use rockets for military purposes we call them missiles and when used for entertainment they can be toys or pyrotechnics.

The composition of the first rocket was what is now in aeronautics called a solid rocket. This rocket runs on a solid fuel that burned inside the rocket. The heated exhaust is expelled out the bottom the rocket, creating the thrust needed to fly. The composition of solid fuel rockets is still pretty much the same as in ancient times.

The casing is the body of the rocket. Rockets were made differently depending upon their end use. For example, solid rockets that were used in space programs had steel casings. The next important element of a solid rocket was the grain. The grain is the solid fuel needed to power the missile. The first types used had gunpowder as the grain but the formula could be altered. If you ever saw a fireworks display, this is why the explosions have different colors. The additions of different metals and composites in the grain of the rockets creates this effect. The final components; the fuse. This was the ignition device used to start the combustion process of the rockets fuel. Later as rocketry was further researched a nozzle was added to the design to better direct exhaust and improve thrust.

The first rockets that were used in modern rocketry was invented by Dr. Robert Goddard. For this he is known as the Father of Modern Rocketry. He created the first successful liquid fuel rocket, adding the nozzle design that is so common today. The liquid fuel rocket ran on a slightly different design than its predecessor with the fuel being released from a pressure tank to a combustion chamber where it was mixed with air or another oxidizer to burn and create heated exhaust which was directed away to create thrust. This would be the design that would pave the way for modern aeronautics and eventually space exploration.

So as we see rockets have come a long way from their earliest day. Nevertheless, they are still playing an important role in the development of human technology. Making new advances possible every day with the missions and experiments they support.

If you enjoyed this article there are other related articles on the Universe Today website you might want to checkout. Here is an article that talks more about solid fuel rockets. If you want to learn more about modern rockets this article on new advances made on liquid fuel rockets.

There are other interesting articles you can find on the web. Time magazine has a great profile article on Robert Goddard. Another good resource is the NASA website which has a brief article on the history of rockets.

You might also enjoy listening to an episode of Astronomy Cast. Episode 100 Rockets is relevant to the stuff talked about in the article.

Source: Wikipedia