Universal wastes are hazardous wastes that are generated by a wide variety of people that contain mercury, lead, cadmium, copper and other substances hazardous to human and environmental health. In general, universal waste may not be discarded in solid waste landfills. Examples of these wastes are batteries, fluorescent tubes, and some electronic devices. The best way to reduce the harmful effects of the wastes on human health and the environment is to reduce consumption. The next best thing is to make sure you DON’T throw them in the trash!
so it is created by God and we should believe on the almighty of God.
Pluto,Two free public programs in Pasadena will offer an overview of the upcoming NASA mission to Pluto. Pluto is the only planet in our solar system not yet studied by a robotic explorer, but not for long. Image right: Artist's concept of Pluto and its moon Charon. Image credit: NASA + Browse version of image Dr. Bonnie Buratti, a New Horizons science team co-investigator from NASA's Jet Propulsion Laboratory, Pasadena, Calif., will talk about the mission on Thursday evening, Nov. 17, at JPL and on Friday evening, Nov. 18, at Pasadena City College. Now at the NASA Kennedy Space Center in Florida, the spacecraft is scheduled for launch on Jan. 11, 2006. JPL will provide the communications coverage for the mission via NASA's Deep Space Network. Buratti's?major interest is in whether there has been geologic activity on Pluto in the recent past and whether Pluto has seasons. She is also interested in the surface composition and texture of Pluto and the Kuiper Belt Objects, millions of asteroid-like bodies from outside the orbit of Pluto, which scientists hope to observe. A native of Pennsylvania, she holds a bachelor's degree in earth and planetary sciences from the Massachusetts Institute of Technology, Cambridge, Mass., and a Ph.D. in astronomy and space sciences from Cornell University in Ithaca, N.Y. She is currently a science team member on the Cassini-Huygens mission to Saturn. NASA's New Horizons mission will be the first to visit Pluto and its largest moon, Charon. The compact spacecraft carries seven science instruments for examining the geology, composition, surface, temperature and atmospheric structure of the planet and its main moon. The science team is studying whether New Horizons will be able to obtain data on the two recently discovered smaller moons of Pluto. The Johns Hopkins Applied Physics Laboratory in Laurel, Md., manages the mission and will operate the spacecraft for NASA.
Mercury, the smallest of the terrestrial planets, orbits at an average distance of 0.39 AU from the Sun, with an orbital period of 88 days and a rotation period of 59 days. Its diameter is about one-third of the Earth's, and its mass about 5% of the Earth's. The high density of Mercury comes from the fact that it has a large iron core, which occupies about 75% of the planet's volume. This core is responsible for the generation of Mercury's magnetic field.
Mariner 10 image of Mercury
Most of our knowledge regarding Mercury comes from 3 encounters by the Mariner 10 mission in 1974-1975. Images taken by the spacecraft revealed a barren, heavily-cratered surface.
Environment
Mercury is a very hostile environment: temperatures range from 400C during the daytime to -170C at night. It has a very thin atmosphere of oxygen, sodium and helium, but the low gravity means that this atmosphere is continually evaporating and being replenished by incoming material from the solar wind. The lack of a thick atmosphere accounts for the heavily-cratered surface of the planet.
Surprisingly, radar observations of Mercury taken in 1991 showed the presence of highly-reflective regions at the planet's north pole, with the signature of ice at low temperatures. Many scientists now believe that ice can survive in steep-sided craters on Mercury's poles, where it is shielded from direct sunlight and therefore escapes being evaporated. It is thought that the ice may have arrived there from cometary impacts, or from the outgassing of water vapour from the planet's interior.
Radar observations of Mercury
It is hoped that NASA's MESSENGER mission will resolve the question of Mercury's polar ice, and also answer other puzzles concerning the planet. The spacecraft is due for launch in spring 2004, and will commence orbit around Mercury in 2009, where it will spend a year collecting data. Amongst other instruments, it will be carrying a gamma-ray and neutron spectrometer (GRNS), which can be used to establish once and for all whether the reflective polar regions are indeed made of ice.
Mercury: Prospects for Life
Even though ice may exist on Mercury, the prospects for life are poor. Any ice which reached high enough temperatures to thaw would instantly evaporate and be lost into space. Furthermore, the proximity of Mercury to the Sun means that the levels of UV radiation are probably too high for life to survive there. To date, there is no evidence for life on the planet.
Mariner 10 image of Mercury
Most of our knowledge regarding Mercury comes from 3 encounters by the Mariner 10 mission in 1974-1975. Images taken by the spacecraft revealed a barren, heavily-cratered surface.
Environment
Mercury is a very hostile environment: temperatures range from 400C during the daytime to -170C at night. It has a very thin atmosphere of oxygen, sodium and helium, but the low gravity means that this atmosphere is continually evaporating and being replenished by incoming material from the solar wind. The lack of a thick atmosphere accounts for the heavily-cratered surface of the planet.
Surprisingly, radar observations of Mercury taken in 1991 showed the presence of highly-reflective regions at the planet's north pole, with the signature of ice at low temperatures. Many scientists now believe that ice can survive in steep-sided craters on Mercury's poles, where it is shielded from direct sunlight and therefore escapes being evaporated. It is thought that the ice may have arrived there from cometary impacts, or from the outgassing of water vapour from the planet's interior.
Radar observations of Mercury
It is hoped that NASA's MESSENGER mission will resolve the question of Mercury's polar ice, and also answer other puzzles concerning the planet. The spacecraft is due for launch in spring 2004, and will commence orbit around Mercury in 2009, where it will spend a year collecting data. Amongst other instruments, it will be carrying a gamma-ray and neutron spectrometer (GRNS), which can be used to establish once and for all whether the reflective polar regions are indeed made of ice.
Mercury: Prospects for Life
Even though ice may exist on Mercury, the prospects for life are poor. Any ice which reached high enough temperatures to thaw would instantly evaporate and be lost into space. Furthermore, the proximity of Mercury to the Sun means that the levels of UV radiation are probably too high for life to survive there. To date, there is no evidence for life on the planet.
Venus,
With the exception of Earth, Venus is the largest of the terrestrial planets, with a diameter of 95% of Earth's. It is similar to Earth in a number ways, with a mass 80% of Earth's, and a slightly lower density. However, its orbit is significantly closer to the Sun, with a mean radius of 0.72 Au. Furthermore, Venus's rotation is very slow, with a period of 243 days, longer than the Venusian year of 225 days!. The slow rotation is probably the reason why Venus does not possess a significant global magnetic field.
Venus Environment
Unlike Mercury, Venus has a thick atmosphere, which accounts for the planet's high albedo of 0.57. The first close-up study of Venus was undertaken by the Mariner 2 spacecraft, which revealed high surface temperatures (in excess of 400C), and very little water in the planet's atmosphere.
The Mariner 2 spacecraft
More recent studies of Venus have revealed that the atmosphere is primarily comprised of carbon dioxide, with smaller amounts of sulphur dioxide, sulphuric acid and hydrogen sulphide. As discussed in [link:diploma-3Lecture 3], the presence of these gasses in Venus's atmosphere led to a runaway greenhouse effect, where incoming radiation from the Sun was trapped, causing the continual rise in the planet's temperature.
The source of Venus's atmosphere was outgassing from volcanic activity, which accounts for the high levels of sulphur. The Magellan spacecraft, which orbited Venus in 1990 and measured the plant's terrain, found evidence that this volcanic activity was still occurring in the planet's recent past (10 million years ago), and may be continuing today.
Computer-generated image of Maat Mons, one of Venus's volcanoes
Prospects for Life
Like Mercury, the prospects for life on Venus appear to be poor. There is very little water on the planet, since most of it has been lost through photodissociation (see [link:diploma-3Lecture 3]). What water does remain has no chance of being liquid on the surface, since the temperatures there are far too high.
However, recent evidence has caused some scientists to rethink their views of life on Venus. The presence of sulphur dioxide and hydrogen sulphide together in the atmosphere is puzzling, since these gasses quickly react with one another and are destroyed. Although volcanic activity can replenish the gasses, the fact that their concentrations are highest far above ground level (around 50km) suggests something else might be going on.
Temperatures within Venus's atmosphere
Pressures within Venus's atmosphere
Interestingly, at around 50km above the Venusian surface, the temperature ranges between 30C and 80C (see figure above), allowing water to condense into droplets. Furthermore, the pressure is similar to Earth's sea-level pressure. It is conceivable that acidophiles may exist in these droplets, accounting for the unusual concentrations of sulphur dioxide and hydrogen sulphide.
Ultraviolet image of Venus
Support for the existence of such lifeforms comes from ultraviolet images of Venus, which show dark patches and bands. If living organisms in the Venusian clouds were synthesizing food using a form of anoxygenic photosynthesis, they would absorb UV radiation and lead to the dark patches observed.
To resolve whether there is indeed life on Venus, further missions to the planet are needed. As part of its trip to Mercury, a fly-by of Venus is scheduled for the MESSENGER mission (see above). More significantly, the European Space Agency (ESA) has now approved the Venus Express mission, after some uncertainty.
The Venus Express spacecraft
Venus Express will leave for Venus in December 2005, arriving at the planet the following summer. It will spend 2 Venusian days (around 500 Earth days!) orbiting the planet, performing an analysis of the atmosphere and surface.
With the exception of Earth, Venus is the largest of the terrestrial planets, with a diameter of 95% of Earth's. It is similar to Earth in a number ways, with a mass 80% of Earth's, and a slightly lower density. However, its orbit is significantly closer to the Sun, with a mean radius of 0.72 Au. Furthermore, Venus's rotation is very slow, with a period of 243 days, longer than the Venusian year of 225 days!. The slow rotation is probably the reason why Venus does not possess a significant global magnetic field.
Venus Environment
Unlike Mercury, Venus has a thick atmosphere, which accounts for the planet's high albedo of 0.57. The first close-up study of Venus was undertaken by the Mariner 2 spacecraft, which revealed high surface temperatures (in excess of 400C), and very little water in the planet's atmosphere.
The Mariner 2 spacecraft
More recent studies of Venus have revealed that the atmosphere is primarily comprised of carbon dioxide, with smaller amounts of sulphur dioxide, sulphuric acid and hydrogen sulphide. As discussed in [link:diploma-3Lecture 3], the presence of these gasses in Venus's atmosphere led to a runaway greenhouse effect, where incoming radiation from the Sun was trapped, causing the continual rise in the planet's temperature.
The source of Venus's atmosphere was outgassing from volcanic activity, which accounts for the high levels of sulphur. The Magellan spacecraft, which orbited Venus in 1990 and measured the plant's terrain, found evidence that this volcanic activity was still occurring in the planet's recent past (10 million years ago), and may be continuing today.
Computer-generated image of Maat Mons, one of Venus's volcanoes
Prospects for Life
Like Mercury, the prospects for life on Venus appear to be poor. There is very little water on the planet, since most of it has been lost through photodissociation (see [link:diploma-3Lecture 3]). What water does remain has no chance of being liquid on the surface, since the temperatures there are far too high.
However, recent evidence has caused some scientists to rethink their views of life on Venus. The presence of sulphur dioxide and hydrogen sulphide together in the atmosphere is puzzling, since these gasses quickly react with one another and are destroyed. Although volcanic activity can replenish the gasses, the fact that their concentrations are highest far above ground level (around 50km) suggests something else might be going on.
Temperatures within Venus's atmosphere
Pressures within Venus's atmosphere
Interestingly, at around 50km above the Venusian surface, the temperature ranges between 30C and 80C (see figure above), allowing water to condense into droplets. Furthermore, the pressure is similar to Earth's sea-level pressure. It is conceivable that acidophiles may exist in these droplets, accounting for the unusual concentrations of sulphur dioxide and hydrogen sulphide.
Ultraviolet image of Venus
Support for the existence of such lifeforms comes from ultraviolet images of Venus, which show dark patches and bands. If living organisms in the Venusian clouds were synthesizing food using a form of anoxygenic photosynthesis, they would absorb UV radiation and lead to the dark patches observed.
To resolve whether there is indeed life on Venus, further missions to the planet are needed. As part of its trip to Mercury, a fly-by of Venus is scheduled for the MESSENGER mission (see above). More significantly, the European Space Agency (ESA) has now approved the Venus Express mission, after some uncertainty.
The Venus Express spacecraft
Venus Express will leave for Venus in December 2005, arriving at the planet the following summer. It will spend 2 Venusian days (around 500 Earth days!) orbiting the planet, performing an analysis of the atmosphere and surface.
