Overview of

Dr. James E. Payne Dr. Donald K. Walter

South Carolina State University June 6, 2000 Outline

I. NASA Overview II. Space Science & Astrophysics III. Structure of the Universe A. B. C. Extragalactic Astronomy & IV. Electromagnetic Radiation V. VI. Instruments & Detectors NASA OVERVIEW

• Mission Advance and communicate scientific knowledge and understanding of the Earth, the solar system, and the universe, and use the environment of space for research.

Explore, use, and enable the development of space for human enterprise.

Research, develop, verify, and transfer advanced aeronautics, space, and related technologies.

NASA Enterprises

NASA HQ and all Field Centers

Office of Earth Human Office of Space Science Exploration and Aero-Space Science Enterprise Development of Technology Space NASA Enterprises

• Space Science – everything above 60 km • Earth Science – everything below 60 km • HEDS (Human Exploration and Development of Space) • Aero-Space Technology is aeronautics, spacecraft development, new technologies NASA Field Centers NASA-Related Projects at SCSU

• CNRT - Center for Network Resources & Training • SWAPOP II – A MASTAP Project • ERC -- Educator Resource Center • Planetarium -- shows & museum exhibits • BCO Hub – NSF, but supports many NASA projects • PAIR – A college curriculum enhancement project *********************************************** • SCSGC -- South Carolina Space Grant Consortium • CASS – Center for Automated Space Science • Space Telescope Science Institute Space Science & Astrophysics Q. What is Space Science? A. Everything from the middle levels of Earth's atmosphere (~ 60 kilometers up) to the edge of the universe billions of light years away. Includes astronomy, solar physics, , magnetospheric physics, chemistry of the upper atmosphere,

URL: http://spacescience.nasa.gov/ Astronomy vs. Astrophysics

• Essentially the same • Astronomy is generally more descriptive • Astrophysics is more rigorous application of laws of physics to study of the universe beyond the earth • Used interchangeably • Astronomy is an observational (not experimental) science Structure of the Universe Solar System Astronomy

• • Planets – Terrestrial (earth-like) – Jovian (Jupiter-like) • Debris – Pluto & Charon – Asteroids – Comets – Meteoroids & Dust Sun

• Sun is the solar system • 99.99% of solar system mass • Gravitationally binds all else • Main source of energy (electromagnetic) • 5 billion years old • Will live another 5 billion • Stability made it possible for life to form and evolve Terrestrial Planets

• Size similar to Earth (3,600-8,000 mi. diameter • Largely made up of the more massive elements (Si, Fe, O, etc.) • Few or no satellites • Four closest to sun – (Mercury, Venus, Earth, Mars) Mercury Venus

Earth Mars Jovian Planets

• Larger than Terrestrial Planets (4-11 x Earth) • Largely made up of the less massive

elements (H, He) and “light” gases (NH3, CH4) • Many satellites • All have ring systems • Four furthest from the sun – (Jupiter, Saturn, Uranus, Neptune) Jupiter Saturn

Uranus Neptune Debris

• Pluto & it’s moon Charon (not quite a planet) • Asteroids up to 600 mi. diameter, mostly in region between Mars & Jupiter, rock makeup • Comets are frozen chunks of water and gases which spend most of their lives beyond the orbit of Pluto • Meteoroids small chunks of rock & metal Pluto & Charon Asteroid

Comet Meteor Formation of the Solar System

• Observed current characteristics of planetary orbits, rotation on axes, etc resulted from original conditions at the time of formation of the solar system • Over millions of years a large cloud of dust & gas 1. Slowly contracts and spins 2. Cold (50 K), gas & dust stick together, buildup in size to larger & larger “chunks” of matter 3. Most matter concentrated toward center (Sun) 4. Clumpy regions grow to size of planets 5. Temperature at center to 15x106 K, fusion begins 6. Sun becomes a star, blasts away gas and lighter elements from inner regions to outer regions 7. Outer planets grow larger, inner planets stay fixed in size 8. Comets, asteroids and other debris left behind Structure of the Universe Galactic Astronomy

• Our solar system part of the -- gravitationally bound group of stars totaling 600 million times the mass of the sun. • Believe the Milky Way looks like other spiral • Components of the galaxy – Stars – Interstellar Medium (Gas & Dust) Stars

• Sun’s mass: 1030 kg • Stellar masses: 10-1 – 103 solar • Solar surface temperature 6x103 K or 12,000 oF • Stellar surface temperatures: 2000 K 100,000 K • Stellar lifetime: 1x106 to 1x1012 yr • The more massive, the short life • End of life produces spectacular objects such as planetary nebulae, supernovae. Planetary Nebulae Existing & Future Supernovae Stellar Birth • Stars form from collapsing clouds of dust and gas

Stars Cluster

Stars are bound together by gravitational attraction into small systems such as binaries on up to large clusters of stars with as many as 1 million members. The example to the right is M80, a globular cluster in the Milky Way galaxy. Structure of the Universe Extragalactic Astronomy

• “Normal” galaxies belong to 3 general categories: spiral, elliptical and irregular • Range in mass from a few million times solar mass to more than 1 trillion solar masses • These types to not evolve one to the other. The type is determined by conditions at the time of formation of the galaxy, such as total mass present, amount of angular momentum, etc.

Galaxies Cluster Active Galaxies • Many galaxies have highly energetic processes going on inside the galaxy such as one or more of the following – bursts of star formation – colliding with each other – have super-massive black holes at their center

• Variety of names depending on the process: – Starburst Galaxies – – Radio-Active Galaxies – Seyfert Galaxies Massive black hole at center of galaxy is 300 million times solar mass

Galaxy with very active star formation taking place

Origin of the Universe • 1929 showed all galaxies moving away from each other due to expansion from original explosion • Expansion like separation of raisins in bread as it heats • Big Bang Theory – 12-15 billion years ago all matter concentrated small region – Explosion threw matter out in all directions, expanding universe – As matter cooled and formed large clumps – – Protogalaxies cool and stars form in the new galaxies – Current time frame – Future of universe in doubt; • (1) will it expand forever while all matter cools off and universe grows dark; or, • (2) if there is enough matter present in the universe, it will slow and eventually halt the expansion (gravity), reverse the direction of motion so now have an infall. Universe collapses and another Big Bang takes place.