Broadcast: January 20, 2004
This is Science in the News, in VOA Special English. I'm Sarah Long.
And I'm Bob Doughty. This week -- the news from Mars ... and a report on President Bush's plan for space exploration.
Plus a warning from scientists who study life, and its future, here on Earth.
Scientists are excited about the progress of Spirit, the American exploration vehicle on Mars. It landed January third to look for environmental conditions that could have supported life. Engineers and scientists cheered as the spacecraft sent its first pictures.
Spirit landed on target in the Gusev Crater, an area fifteen degrees south of the Martin equator. Scientists chose the Gusev Crater based on evidence that it may have been an ancient lake.
Hours after landing, the spacecraft began to send detailed pictures of the surrounding area.
Spirit traveled four-hundred-eighty-seven-million kilometers to reach Mars. It stayed in place on its lander for more than a week. NASA officials wanted to make sure all the equipment worked before they told the rover to drive onto the surface.
There was a delay. They had to turn the vehicle away from airbags that softened the landing but then blocked the desired path. Last Thursday the controllers again cheered as they declared that all six wheels of the rover were on Martian soil.
Special cameras and devices to identify minerals helped engineers and scientists decide which direction to send the rover first. Spirit has a robotic arm to collect rocks and soil to study them for evidence of water in the past.
Spirit was launched from Florida last June. NASA launched a second spacecraft in July, called Opportunity. Opportunity will land on Mars in a few days if all goes as planned,. The landing area chosen is called the Meridiani Planum. It is on the other side of the planet from where Spirit landed. NASA officials say the two areas are very different.
Like Spirit, Opportunity weighs about one-hundred-eighty kilograms. The two rovers are expected to travel no more than forty meters each Martian day to search for evidence of water. A Martian day is about the same length as an Earth day. The exploration is supposed to continue for at least three months.
On Earth, almost everywhere liquid water exists, so does life. Today Mars is cold and dry, with huge dust storms. Scientists say life cannot exist. But evidence from past landings suggest the red planet was once warmer. Experts say water could have flowed in lakes or even oceans.
President Bush has proposed to send people to Mars. Before that, however, robotic spacecraft would go to the moon to prepare for the return of humans.
People would return to the moon sometime between two-thousand-fifteen and two-thousand-twenty. They would go on a new kind of spaceship to be developed, called the Crew Exploration Vehicle.
Crews would establish a moon base for scientific research. Later, that base could be used to launch explorers farther into space.
Mister Bush visited NASA headquarters in Washington last week to announce the plan to explore what he called "worlds beyond our own."
The first goal is to complete the International Space Station by two-thousand-ten. Fifteen other nations are also involved in the program. Mister Bush says the station is needed to study the long-term effects of radiation and weightlessness on health. He says there is much to learn before human crews can travel through space for months at a time.
NASA will need its current space shuttles to complete the station. But Mister Bush says the three shuttles will be retired after that. NASA has not launched a shuttle since the Columbia broke apart on re-entry into the atmosphere last February first. Seven astronauts were killed.
Mister Bush said the United States will invite other nations to join his plans in what he called a spirit of cooperation and friendship. Last October, China sent its first person into orbit around Earth in a test as the Chinese develop a space program.
Mister Bush says he wants Congress to add one-thousand-million dollars to the NASA budget over the next five years. In addition, NASA would move eleven-thousand-million dollars away from existing programs. The current five-year budget plan for the agency is eighty-six-thousand-million dollars.
Mister Bush's father, when he was president, also proposed setting up a moon base and sending people to Mars. The older President Bush announced his plan in nineteen-eighty-nine. He did so to mark twenty years since the first moon landing. But that plan called for a much bigger budget and did not succeed.
Critics call the new plan a political move in an election year. They say the money would be better spent at home. But President Bush said in his speech: "We chose to explore space because doing so improves our lives and lifts our national spirit. So let us continue the journey."
In the early nineteen-sixties, President John F. Kennedy declared the goal to put a man on the moon. The space program began as a race with the Soviet Union. The Soviets were the first to reach space. But the United States was the first -- and so far only -- country to land people on the moon. The last of six Apollo landings took place in December of nineteen-seventy-two.
International researchers say climate warming caused by human activity could lead to the destruction of hundreds of kinds of plants and animals in the next fifty years. Most scientists think climate change, or global warming, results from the release of carbon dioxide and other gases. Industrial production and vehicles release these gases. The gases trap heat in the atmosphere.
The nineteen scientists studied more than one-thousand-one-hundred species of plants and animals in land areas around the world. They published their study in the magazine Nature.
The researchers gathered information from earlier studies. These included examinations of animals that live in deserts, wetlands, cool climates and other habitats in five areas of the world. The scientists used several computer models on expected climate change. The models were divided into levels of possible severity, from moderate to extreme climate change.
The researchers joined these models with maps of the different kinds of environments in which the species lived. These maps provided information about what each species needed from its environment and how climate change would affect those needs. Then they studied where those species might have to move in cases where their needs could no longer be met.
The scientists found that between fifteen and thirty-seven percent of the species they studied will disappear in fifty years if climate change continues.
VOICE TWO:There are more than fourteen-million known species of plants and animals on Earth. Study leader Chris D. Thomas says it would be helpful to include more in the examination. But, he also said there is no reason to think the findings would change greatly if more species were included. Mister Thomas is a scientist at the University of Leeds in Britain.
Townsend Peterson of the University of Kansas in the United States was another study team member. He says there are a number of reasons people should be concerned about the threatened extinction. He says the information loss from destruction of a species is one concern.
For example, a threatened plant may contain a substance that could be used to make an important medicine. But, Mister Peterson says humans should also care because each species is a part of the natural history of the planet.
Other scientists criticized with the study. One scientist said it is too difficult to see into the future and predict results fifty years from now. Another scientist said the study did not recognize the ability of species to change or adapt in order to live in higher temperatures.
SCIENCE IN THE NEWS was written by Caty Weaver, Avi Arditti and Cynthia Kirk, who was also our producer. This is Sarah Long.
And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.