Energy from Natural Gas
1. Much of the world gets its energy from fossil fuel sources, including coal, oil, and natural gas, all of which were created millions of years ago.The process began with dead plant and animal matter that collected and over time was buried deep within the earth. There, exposed to extreme pressure and temperatures, the carbon-based material underwent various chemical and physical changes. Some of it became coal, some oil, and some natural gas, depending on the exact conditions it was subjected to.
2. Natural gas is both invisible and odorless.During the first century of the fossil fuel era, it was disregarded as a worthless byproduct of coal and oil. However, people later discovered that it could also be a useful source of energy, and they set about trying to realize its potential. Its use began to grow in the twentieth century and has increased rapidly within the last 40 years. Nowadays, natural gas is employed all over the world to heat homes, generate electricity, power factories, and even fuel vehicles.
3.Because it was created through the same process as other fossil fuels, natural gas can often be retrieved from oil fields, something known as an associated source.Coal beds have similarly been known to yield natural gas. In addition, there are isolated deposits containing only gas that are referred to as non-associated sources. To access a subterranean natural gas pocket, a hole is drilled down into it, just as in oil extraction. However, due to the gas’s lightness, it will rise to the surface on its own instead of having to be pumped out.
4. The compound we know as natural gas is actually a composite of several different substances, the primary one being methane gas.Each deposit has a unique makeup, but other common components of natural gas include propane, butane, and sulfur.Borrowing terms used in the description of oil, natural gas with a high sulfur content is called "sour" while that with a low content is referred to as "sweet" Regardless of the exact composition, natural gas must be refined to remove its impurities; when ready for use, it is nearly pure methane.
5. Natural gas offers many advantages as a fuel source, the first and most important being that it is extremely clean burning. While oil and coal both have complex molecular structures, methane’s is simple: one carbon atom surrounded by four atoms of hydrogen. The lack of excess particles translates into fewer waste byproducts during combustion. For example, all fossil fuels produce carbon dioxide when burned, but natural gas releases substantially less carbon dioxide than other fuels. Given the major role of carbon dioxide in the acceleration of global warming, this is an important attribute. In addition, natural gas emits far less nitrogen and sulfur, which are key contributors to the smog that pollutes the air in metropolitan areas, as well as acid rain.
6. The benefits of natural gas extend far beyond its cleanliness. Since it contains fewer waste particles, its energy can be acquired with much more efficiency than that of the other fossil fuels, meaning a lower overall cost for the consumer.
Another advantage is that natural gas is transported via underground pipelines instead of by ships and trucks.
Finally, natural gas is relatively plentiful and widespreaD、
Geologists have identified extensive stores inCanada, the United States, Russia, the MiddleEast, andAustralia, among other locations.
With the world’s oil supplies quickly dwindling, it is becoming more important than ever to utilize alternative energy resources such as natural gas.
7. Of

American Race to the Moon
The roots ofAmerica’s plan to land a man on the moon can be found outside of the country.Although never directly mentioned in its official motto, the NationalAeronautics and SpaceAdministration (NASA、was established as a direct result of the Soviet space program’s successful launching of Sputnik 1, the first man-made satellite, on October 4th, 1957. The U.S.Congress, worrying that the country was about to lose its technological edge over the rest of the world, demanded drastic action.Dwight
D、Eisenhower, then president, waited only a few months before creating a new government agency responsible for all non-military activity in space. On July 29th, 1958, the president signed the NationalAeronautics and SpaceAct, creating NASA、The outside world continued to have an effect. The technology initially used by NASA、came in large part from the German rocket program of the Second World War. Wernher vonBraun, who was recruited by theAmericans at the end of the war, is today considered the father of the United States space program.
NASA、began operations on October 1st, 1958, and was made up of four laboratories as well as about eight thousand employees from the already 43-year-old NationalAdvisoryCommittee forAeronautics. The history of the new organization can be divided into various phases, each related to a specific program. The first experiments undertaken as part of Program Mercury were designed simply to discover if humans could actually survive a round-trip voyage into space. This involved the construction of 20 spacecraft, each large enough to hold one astronaut. On a very basic level, NASA、needed to test what worked and what didn’t. They made numerous unmanned launches, many of them resulting in explosions, as well as four separate launch attempts that included small creatures. The first was a small monkey.By 1961, NASA’s Program Mercury successfully placedAlan Shepard into space, but for only fifteen minutes.
This milestone quickly led to theApollo Project. The initial idea was to get a human close to the Moon, but not actually on it. There were too many unknowns about the surface of the Moon to plan a safe landing. On February 20th, 1962, John Glenn piloted the Friendship 7 for five hours in orbit around theEarth. NASA、had finally learned how to get a human into space, and most importantly, keep him there. This was the crucial step necessary: they had created the ability to stay in space long enough to really figure out what to do there. The objectives of the mission changed drastically, however, when President JohnE、Kennedy told the nation on May 25th, 1961, thatAmerica would instead focus on a manned mission to and from the Moon, and that these missions would be possible by the end of the decade.
■
A、Many people worried about the money that would be spent, feeling that it would be better used for other purposes. ■
B、Others continued to see the program in relation to the rest of the worl
D、■
C、They worried that NASA、did not seem to have any valuable military use and openly questioned the idea of spending money on rockets that could not be used to defend the country. ■
D、Kennedy managed to convince both sides of the project’s benefits. He assured people that the mission would provide jobs and resources to different states throughout the country as well as specific advances in rocket technology. Kennedy stressed the value of dual-use technology, which could be used for both military and non- military purposes.
Instead of sending a person to space and back again, which required only one lift-off fromEarth followed by a landing, theApollo Project now entailed anEarth lift-off, followed by a landing on the Moon, another lift-off, and then a finalEarth landing. The Gemini Program, therefore, was created to collect information and perfect techniques that would make theApollo Project possible. U

您正在结束答题

请确认是否提交试卷？

继续做题确认提交