Scientists have now found out that the asteroid that hit the earth and led to the extinction of the dinosaurs 65 million years ago also caused a long period of winter and extremely cold temperatures.
The asteroid hit the Yucatan peninsula in Mexico and created a crater with a diameter of 15 km. As a result about three-quarters of all plant and animal species died, including the dinosaurs. The impact sent tons of dust and sulphur gas into the atmosphere.
Now we know that three times more sulphur gas was catapulted into the atmosphere than previously thought. Sunlight was blocked from getting in, which resulted in much lower temperatures. A new study shows that temperatures worldwide dropped to about-10°Celsiusfor at least three yearsafterthe impact. Thus, the earth was plunged into a deadly winter, which many plants and animals could not survive.
While air temperatures probably rose shortly after impact, ocean temperatures may have been affected for centuries. Scientists also found out that the amount of carbon-dioxide that was released into the atmosphere was probably over-estimated.
In new research on the Yucatan peninsula, scientists drilled into the surface of what’s left of the crater and collected rock samples. This allowed them to examine and reconstruct what happened.
affected = to do something that leads to a change later on
asteroid = one of the many small planets that move around the sun especially between Mars and Jupiter
block = stop from getting in
carbon dioxide = gas that is produced when animals or people breathe out or when you burn carbon in the air
catapult = when something moves through the air very quickly
cause = lead to; result in
century= a hundred years
crater = a round hole made by a large object crashing into something
diameter = a straight line from one side of a circle to the other
drill = to make a hole into the surface
drop = go down
examine = look at closely
extinction = when animals or plants die out
impact = crash
over-estimated = less than thought at first
peninsula = land with water on three sides
plunge = here: to suddenly change
previously = earlier
reconstruct = to see how something happened by putting the facts together
release= set free
research = to look at something closely in order to find out more about it
sample = here: rocks that scientists can study and look at
scientist = a person who is trained in science and works in a lab
species = group of animals and plants whose members are similar and who can produce babies together
sulphur gas = a yellow bright substance that burns and has an unpleasant smell
survive = continue to live after a dangerous situation
The American government has released over 3000 documents relating to the assassination of John F. Kennedy in Dallas in 1963. President Trump, however, has ordered some of the documents with sensitive information to be held back for 6 months after a request from the CIA and FBI. In 1992 President George Bush signed a law that required all documents about the JFK murder to be released within 25 years.
The published documents have not provided any sensational new information on the JFK assassination. The public had hoped that the released documents would bring more light into the former president’s murder. Experts say that the decision to withhold some of the documents suggests that the government wants to keep some things secret.
Many of the documents are incomplete and some are only memos. The files show how disorganised government agencies were during the 1960s and how they dealt with the assassination.
In a series of memos, the FBI reports on Lee Harvey Oswald’s visit to Mexico City, where he met with a Soviet agent shortly before the Kennedy was killed. The material shows that authorities were trying to find out if a foreign government – Cuba or possibly the Soviet Union – was behind Kennedy’s death.
There is still no evidence that there was a conspiracy to kill the president. Nothing suggests that Lee Harvey Oswald worked with a partner. There are, however, FBI documents that warned the Dallas police about a threat against Oswald. Kennedy’s killer was shot dead at the Dallas Police Department two days after the Kennedy assassination.
Among the documents are reports that are only indirectly related to the Kennedy killing, for example CIA plans to murder Cuba’s Fidel Castro .
agency = organisation or department in the government
agent = person who works for another government
assassination = the murder of an important person
authorities = organisation or department in the government
conspiracy = a secret plan made by two or more people to do something that is against the law
deal with = handle
decision = to do something after you have thought about it
disorganised = without a plan or system
evidence = proof that something happened
files = documents
foreign = from another country
former = earlier, in the past
government = the people who rule a country
incomplete = not having everything that should be there
provide = to give; make available
public = ordinary people in a country
publish = to make public
relating to = about
release = to make public for everyone to see
request = a formal demand for something
require = here: the law says you have to do something
secret = not for everybody to know
sensitive = something that you have to deal with carefully
series = a few
sign = to put your name on a document
Soviet Union = largest Communist country that existed between 1917 and 1991
threat = when someone says that they want to harm or trouble you
Easter Island , or Rapa Nui as the natives call themselves , belongs to the remotest places on earth. The Chilean island, famous for its carved statues, is located in the middle of the southern Pacific Ocean.
For decades, scientists have been wondering how the natives got to the island before the first Europeans came in 1722. Most experts think that the first settlers came to Easter Island at around 1200 A.D. , probably on small boats crisscrossing the Pacific Ocean.
Other anthropologists have been trying to find out if the natives have any connections to early South Americans, three thousand kilometres away. Latest research now claims that the Easter Islanders were, in fact, more isolated than previously thought.
Scientists have been examining the skeletons and bones of five people that go back hundreds of years. However, they have found no evidence that suggests they have might have ancestors in South America.
The first theory of South American ancestry came up when Thor Heyerdahl saw sweet potatoes when he arrived there in the 1950s. He also found people using fishing tools that South Americans also used. Scientists at that time thought the people of the Easter Islands may have sailed to South America and back again some time before the Europeans came.
ancestor = a member of your family who lived a long time ago
anthropologist = a person who studies people , their cultures and where they come from
carved = to cut an object with a knife
claim = to say that something is true even if you cannot prove it
Chilean = from Chile
crisscross = to travel many times back and forth without a certain pattern ; zigzag
decade = ten years
evidence = facts that clearly show that something is true or exists
examine = to look very closely at an object
however = but
isolated = here: to be alone and far away from others
located = can be found
native = a person who was born in a country or place
previously = earlier
remote = very far away from civilisation
research = the study of a subject in order to find out new facts
sail = the wind brings you somewhere on a boat
scientist = a person who is trained in science and works in a lab
settler = a person who goes to live in a place where not many people have lived before
sweet potato = a vegetable that looks like a red potato ,is yellow inside and tastes sweet
Che Guevara was a Marxistrevolutionary who was a close aide of Fidel Castro during the Cuban Revolution. He was killed in Bolivia 50 years ago.
Che was born into a middle class Argentinian family in 1928 and studied medicine in his youth. From the beginning he was influenced by left-wing ideas and strongly opposed the government of Argentine leader Juan Peron.
Instead of finishing his studies, the young rebel decided to travel around South America, where he witnessedwidespread poverty and oppression among the population. In the 1950s he travelled to Guatemala where he saw how the CIA helped overthrow a leftist government.
In Mexico, Che Guevara met Fidel Castro and his brother Raul. Together , they planned to overthrow the pro-western government in Cuba. After Castro took power in 1959 , Che Guevara held some top posts in his government and also became Castro’s military adviser. He strongly opposed the United States and its policies. Instead he tried to strengthenties with the Soviet Union and spread socialism to Central America.
The Marxist revolutionary was sent to developing countries in order to show them how Cuban socialism worked. In Congo, he trained rebels to fight against government soldiers. Che Guevara was finally captured in Bolivia where he was he was executedin 1967.
adviser = person who gives you advice because they know a lot about a topic
aide = person who helps a politician or leader
capture = to catch a person and keep them as a prisoner
developing country = poor country in Africa, Asia or America
execute = to kill someone as a from of being punished
influence = to affect or change the way someone behaves or thinks
instead = in something’s place
government = the people who rule a country
Marxist = person who supports the ideas of Karl Marx. He explained changes in history as a result of the struggle between social classes
oppose = to be against
oppression = when you treat a group of people in an unfair way and do not give them the same rights that others have
overthrow = remove a leader or a government
policy = the way a government plans to handle a topic or problem
poverty= the situation of being poor
revolutionary = person who joins or supports a revolution
socialism = system in which many industries are owned by the state and rich people pay more taxes than poorer ones
strengthen = make stronger
take power = here: become a leader or the head of a government
60 years ago , on October 4th, 1957, the Soviet Unionlaunched the first man-made satellite into space. Sputnik showed that the Soviets were willing to overtake American technology. The launch was also the beginning of a new episode in the Cold War – the Space Race.
Sputnik looked like a big basketball and weighed 84 kilograms. Two radio transmitters and four antennae were attached to it. The satellite sent out a beeping signal and could be seen on Earth with the naked eye.
The Soviet satellite orbited the Earth over 1,400 times in a period of three months before it burned up in the atmosphere. A month later Sputnik 2 was launched, this time with the first animal on board, a dog named Laika.
Sergei Korolev was the father of the Soviet space program. He oversaw the creation of a booster rocket that sent Sputnik into orbit. Korolev was also responsible for bringing German engineers to the Soviet Union after World War II.
While Sputnik took the rest of the world by surprise, the Soviet Union told their people about the historic launch only a few days later.
In January 1958 the Americans were able to launch their first satellite into orbit. Explorer I remained in orbit until 1970 and was the first satellite to detect the Van Allen radiation belt. Later that year Congress passed a law that created NASA , the American space agency.
antenna = a long piece of wire used to receive radio or television signals
atmosphere = the mixture of gases that is around the Earth
booster rocket = a rocket that has enough power to send a satellite into Earth orbit
Cold War = unfriendly relationship between the USA and the Soviet Union after World War II
detect = to show that something existed
engineer = here: person who can understands how to build rockets and satellites
episode = time during which something happens
launch = start ; here: send into space
naked eye = without the help of a telescope
orbit = to go around a planet or star
oversee = to be in charge of ; the leader of
overtake = here: to do something more quickly than someone else
remain = stay
Soviet Union = largest Communist country in the world ; it existed between 1917 and 1991
space agency = government organisation that controls space travel and the study of space
transmitter = object that sends out radio signals
Van Allen radiation belt = particles of energy that are kept together by the Earth’s magnetic field
Barack Obama has become the first American president to visit Hiroshima. During his recent visit to Japan he visited the city which was destroyed by the first atomic bomb.
Together with Japan’s Prime Minister Shinzo Abe, Obama laid a wreath at the Hiroshima Peace Memorial. In an emotional speech, Obama did not apologize to the Japanese people, but called the dropping of the first atomic bomb the biggest crime in human history. The American president demanded a world without nuclear weapons. The United States would also continue to stand by Japan, which turned from an enemy into an important ally in Asia. After the ceremony, Obama signed the guest book and spoke with survivors.
About 140,000 people were killed on August 6, 1945 when in the first atomic bomb exploded over the city. An additional 70000 died when the second bomb was dropped over Nagasaki. Nine days later Japan surrendered and World War II ended. Tens of thousands died from radiation illnesses in the decades that followed.
Obama did not mention the 20 000 Korean victims, who were forced to work for the Japanese in Hiroshima at the time of the bombing.
Although visiting Hiroshima has been a very sensitive issue for past American presidents, polls revealed that most Japanese wanted Obama to visit the city.
additional = extra
ally = a friendly country that you help
although = while
apologize = to say you are sorry for what happened
continue = keep on
crime = an action that is against the law
decade = period of ten years
demand = want, wish for
destroy = to damage completely, so that nothing is left
emotional = with strong feelings
force = make someone do something
lay a wreath = put down a circle of flowers at a place where people have died
memorial = an object or building that has been built to honor a person or a famous event
mention = talk about
nuclear weapon = a bomb that releases energy by splitting atoms; it can kill thousands of people and destroy whole cities
poll = a study in which people are asked about their opinion on a certain topic
radiation illness = here : people who became sick because of the dangerous energy that came from the bombs
recent = a short time ago
reveal = show
sensitive issue = here: something that you have to deal with carefully, so that you do not make others angry
sign = put your name on a document
stand by = support, help when it is needed
surrender = give up
survivor = person who managed to live on after the bombing