What is the difference between a refracting telescope and a reflecting telescope?

A refractor uses mirrors; a reflector uses lenses A refractor uses lenses to bend and focus light; a reflector uses mirrors to reflect and focus light Refractors are used in space; reflectors are used on the ground Refractors observe only infrared; reflectors observe only visible light

Why are most large modern telescopes reflectors rather than refractors?

Reflectors are cheaper to manufacture Refractors can only be used during the day Mirrors can be made much larger than lenses, are lighter, and do not suffer from chromatic aberration Reflectors can see farther into space because mirrors move faster than light through glass

Which two types of electromagnetic radiation pass through Earth's atmosphere well enough for ground-based telescopes to use?

X-rays and gamma rays Infrared and ultraviolet Visible light and radio waves Gamma rays and infrared

What do radio telescopes detect, and what have they been used to discover?

Heat from volcanic planets — used to find volcanically active worlds Radio waves from space — used to discover pulsars, map the structure of the Milky Way, and detect the cosmic microwave background Sound waves from stars — used to listen to stellar vibrations Magnetic fields of planets — used to study planetary cores

Why are infrared telescopes particularly useful in astronomy?

Infrared telescopes can see in any direction without being blocked by the Sun Infrared can penetrate dust clouds that block visible light, and it detects cool objects like young stars, brown dwarfs, and planet-forming disks Infrared telescopes are cheaper and simpler than optical telescopes Infrared is the only type of light that travels at the speed of light

Why do ultraviolet, X-ray, and gamma-ray telescopes have to be placed in space?

Space telescopes are larger and can therefore see more Gravity on Earth bends X-rays, making them impossible to focus Earth's atmosphere absorbs ultraviolet, X-rays, and gamma rays before they reach the ground These wavelengths only exist beyond Earth's orbit

What do X-ray telescopes reveal that optical telescopes cannot??

Cold, icy comets in the outer solar system Extremely hot plasma around black holes and neutron stars, supernova remnants, and galaxy cluster gas at millions of degrees The visible surfaces of nearby stars Rocky planets orbiting other stars

What is NASA's primary X-ray space telescope?

Hubble Space Telescope James Webb Space Telescope Chandra X-ray Observatory Spitzer Space Telescope

Why must infrared telescopes be either cooled to very low temperatures or placed far from Earth?

Infrared detectors stop working at room temperature The telescope itself and surrounding warm objects emit infrared radiation that would overwhelm the faint infrared signals from space Earth's gravity bends infrared waves, distorting images Infrared light cannot travel through empty space without cooling

Which type of telescope is best suited for studying young stars still hidden inside their birth clouds of gas and dust?

Gamma-ray telescope, because it has the most energy Radio telescope, because radio waves travel through anything Infrared telescope, because infrared light penetrates the dust that blocks visible light from young stars X-ray telescope, because young stars are very hot

Why is observing the universe across multiple wavelengths (multi-wavelength astronomy) so important?

One type of telescope can see everything — using multiple is just for backup Multi-wavelength astronomy is only needed to find exoplanets Different processes and objects emit different wavelengths, so each type of telescope reveals different objects and phenomena — together they give a complete picture Multiple telescopes working together can amplify each others signals