Unit E Section 3.2 Flashcards
Optical telescopes give us information based on
visible light
What can also emit radio waves, infrared (heat) waves, and X-rays?
However, objects in space, such as stars and galaxies
What are radio waves, infrared (heat) waves, and X-rays?
These are all forms of ELECTROMAGNETIC ENERGY.
What is Wavelength?
is a measurement of the distance from one point on a wave (such as the crest) to the same point on the next wave.
What is Frequency
is the number of waves that pass a single point
in one second.
Energy with a high frequency has what amount of length?
has a short wavelength
Gamma rays, for instance, have a high frequency (1020 waves per second) and a very short wavelength (less than a millionth of a centimeter)
how fast does Electromagnetic energy travel?
This energy travels at the speed of light, 300 000 km/s, but has different wavelengths and frequencies from those of light.
How much frequency do radio waves have?
What about the wavelength
Radio waves have a low frequency,
but wavelengths that can be several kilometers long.
electromagnetic spectrum?
the range of wavelengths or frequencies over which electromagnetic radiation extends.
-The visible light we see all around us occupies a small section of the entire electromagnetic spectrum, which covers the whole range of electromagnetic energy
Visible light has a wavelength
measured in?
micrometers (written as µm)
One micrometer is 1 millionth of a meter
Where are the Radio waves received from in the vast solar system?
from stars, galaxies, nebulae, the Sun, and even some planets—both in our own solar system and in others
signals are mapped through the use
of sophisticated electronics and computers.
What are the advantages of RADIO TELESCOPES:
- Radio waves are not affected by weather and can be detected during the day and at night.
- They are also not distorted by clouds, pollution, or the atmosphere as are light waves.
- astronomers have discovered much about the composition and distribution of matter in space—information that cannot be detected by optical equipment.
Because the wavelengths of radio waves are so large
What should happen to the antennae?
the antenna of a radio telescope
must be large.
What are radio telescopes made of?
metal mesh
Radio telescopes resemble:
Their shape resembles that of a satellite dish: they are curved inward, with a receiver at the middle.
What is the curved position of a radio telescope is what?
-The curved portion of the dish is really a large antenna that intercepts and focuses radio waves before transmitting them to the receiver.
There, the waves are transformed into an electrical signal that is fed into a computer for interpretation.
several small radio telescopes can be combined to
achieve?
to achieve greater resolving power than one large radio telescope can achieve
interferometry?
combining several radio telescopes for better performance and accuracy of radio images.
the bigger the separation between the telescopes (interferometry)…….
the more detail
astronomers can measure.
arrays
more telescopes are arranged into groups called arrays
The benefit of arrays?
The accuracy of measurement is increased
even further if more telescopes are arranged into groups called arrays.
Example of arrays?
The accuracy of measurement is increased
even further if more telescopes are arranged into groups called arrays.
Benefits of infrared spectrum through a radio telescope?
When observed through an optical telescope, a
planet orbiting a distant star is practically invisible because of the light given off by the star
when viewed in the infrared spectrum through a radio telescope, the brightness of the star is reduced and the planet’s brightness peaks.
What are the various sources in space from which radiation comes from?
- infrared image of a young star cluster
- X-rays that are being emitted from objects such as black holes and pulsating stars;
- and huge bursts of gamma rays that appear without warning and then fade
Are bursts of gamma rays predictable?
Bursts of gamma rays occur unpredictably in different parts of space.
Although they may last only a few seconds or minutes, they give off more energy than our Sun would produce in its entire 10-billion-year lifetime.
What are space probes?
Space probes are unmanned satellites or remote-controlled “landers” that put equipment on or close to planets where it would be too difficult or dangerous to send humans to.
What are the achievements of space probes?
Space probes have been used to carry out remote sensing on Mercury and Jupiter, sample soil on Mars, land on Venus, and study the nature of Saturn’s rings
Besides Earth, the only other body in the solar system that has been physically explored by humans is……
the Moon
When was the first trip to the moon by humans accomplished?
Apollo 11 mission in 1969
