Question 1

To determine whether a celestial body is approaching or receding from Earth, astronomers employ ___________.&#10;A) high speed radar&#10;B) the Stefan- Boltzmann law&#10;C) the Doppler principle&#10;D) Einstein's equation&#10;E) telescopic imaging&#10;

Accepted Answer

The Doppler principle is used to determine whether a celestial body is approaching or receding from Earth by analyzing the shift in the wavelengths of light emitted by the object. If the object is moving towards Earth, the wavelengths will appear shorter and shifted towards the blue end of the spectrum (known as a blueshift), while if the object is moving away from Earth, the wavelengths will appear longer and shifted towards the red end of the spectrum (known as a redshift). This method is commonly used in astronomy to study the motion of stars, galaxies and other celestial objects.

Question 2

X- rays have shorter wavelength than visible light; therefore, X- rays___________ .&#10;A) cannot be detected because of their wavelength&#10;B) have lower energy than light waves&#10;C) pass through materials because their photons are smaller than light photons&#10;D) are higher energy than light waves&#10;

Accepted Answer

X-rays have shorter wavelength than visible light, which means they also have higher frequency and higher energy than light waves. Therefore, option D is correct. Option A is not correct because X-rays can indeed be detected using appropriate instruments. Option B is incorrect because X-rays have higher energy than light waves. Option C is partially correct - X-rays can indeed pass through materials, but not necessarily because the photons are smaller than those of light waves. It is due to their high energy and ability to penetrate matter.

Question 3

The wavelength of light emitted from a distance object is related to___________ .&#10;A) gravity-gravity bends electromagnetic waves causing refraction and sorting of wavelengths&#10;B) the energy of the source. A more energetic source has higher wavelength emissions&#10;C) the energy of the source. A more energetic source has lower wavelength emissions&#10;D) distance of the source-the farther away the object is, the lower the wavelength observed related to changes in electromagnetic energy over time&#10;

Accepted Answer

The wavelength of light emitted by an object is directly related to the energy of the source. According to the electromagnetic spectrum, a more energetic source emits light at shorter wavelengths, not higher. This principle is grounded in the physics of electromagnetic radiation, where energy (E) and wavelength (λ) are inversely related, as described by the equation E = hc/λ, where h is Planck's constant and c is the speed of light.

Question 4

The study of spectroscopy was begun by___________ .&#10;A) Galileo&#10;B) Albert Einstein&#10;C) George Hale&#10;D) Niels Bohr&#10;E) Sir Isaac Newton&#10;

Accepted Answer

Sir Isaac Newton began the study of spectroscopy in the 17th century, when he used a prism to separate white light into its different colors and observed the spectra produced by various substances.

Question 5

As the temperature of a radiating surface is increased ___________.&#10;A) a larger portion of the energy is radiated at shorter wavelengths&#10;B) a larger portion of the energy is radiated at longer wavelengths&#10;C) the total amount of energy emitted increases&#10;D) both A and B&#10;E) both A and C&#10;

Accepted Answer

As the temperature of a radiating surface increases, a larger portion of the energy is radiated at shorter wavelengths, according to Wien's displacement law. Additionally, the total amount of energy emitted increases, as described by the Stefan-Boltzmann law.

Question 6

Light travels 300,000 km/s. Many communications satellites are in geosynchronous orbit that means they keep up with Earth's rotation and thus stay above the same spot on earth. at about 36,000 km above Earth's surface. If you talk to your friend on the other side of the world via a geosynchronous satellite using Skype or your phone, what is the minimum time delay there will be between you and your friend in your conversation?

A) .24 seconds
B) 8.3 seconds
C) .12 seconds
D).48 seconds

Accepted Answer

The answer of Light travels 300,000 km/s. Many communications satellites...

Question 7

The intensity of the light emitted and its wavelength tell us about the___________ that is generating the light.&#10;A) exact object&#10;B) type of process&#10;C) distance away the object is&#10;D) part of the solar system&#10;

Accepted Answer

The type of process generating the light is determined by the wavelength and intensity of the light emitted. For example, the characteristic spectral lines emitted by different types of atoms allow us to determine the elements present in a star or galaxy.

Question 8

When excited electrons decay to ground state, hydrogen emits along distinctive line near the visible red. An astronomer observes what appear to be hydrogen emission lines from a distant star but they are in the infrared spectral band. She concludes___________ .

A) the star's hydrogen emission must be being absorbed by water in the atmosphere, which then re- emits in the infrared
B) the star must be moving very fast away from Earth
C) her instrument needs to be recalibrated
D) the star must be moving very fast toward Earth

Accepted Answer

The observation of hydrogen emission lines in the infrared spectral band, rather than in the visible spectrum, suggests that the star is moving away from Earth. This is due to the Doppler effect, where the wavelength of light is stretched (redshifted) when an object is moving away from the observer, shifting the emission lines to longer (infrared) wavelengths.

Question 9

The type of spectrum produced by a common light bulb is a___________ .&#10;A) continuous spectrum&#10;B) bright- line emission. spectrum&#10;C) dark- line absorption. spectrum&#10;D) all of the above&#10;E) none of the above&#10;

Accepted Answer

A common light bulb produces a continuous spectrum, which means it emits light at all wavelengths within the visible spectrum. This is in contrast to a bright-line emission spectrum, which only shows specific bright lines at certain wavelengths, or a dark-line absorption spectrum, which shows specific dark lines where certain wavelengths have been absorbed.

Question 10

The spectra of most stars are dark- line spectra because___________ .&#10;A) elements in the earth's atmosphere absorb in these dark- line bands, blocking out the frequencies in the dark bands&#10;B) electrons decaying to a lower energy state emit a photon at a fixed energy, leaving dark bands between the emissions&#10;C) elements in the Sun's outer atmosphere emit radiation between these dark bands&#10;D) elements in the Sun's outer atmosphere absorb in these dark- line bands, blocking the radiation in those bands&#10;

Accepted Answer

The most common reason for dark-line spectra in stars is that elements in the star's outer atmosphere absorb radiation in certain specific bandwidths, leaving dark bands in the spectra. This phenomenon is known as absorption spectrum. Therefore, option D is correct as it describes this process. Option A is incorrect because it refers to Earth's atmosphere, which is not relevant to the spectrum of stars. Option B is incorrect because it describes emission spectra, which can result in bright lines, not dark lines. Option C is also incorrect because it states that the elements in the Sun's outer atmosphere emit radiation, which is not the reason for dark-line spectra.

Question 11

Electromagnetic radiation that behaves like a particle is called an___________ .&#10;A) electron&#10;B) proton&#10;C) quark&#10;D) photon&#10;

Accepted Answer

The answer of Electromagnetic radiation that behaves like a particle...

Question 12

If a yellow star is moving away from us very rapidly, what color will it appear to be?&#10;A) greenish blue&#10;B) purple&#10;C) bluish purple&#10;D) reddish orange&#10;

Accepted Answer

The answer of If a yellow star is moving away...

Question 13

Light is an electromagnetic wave, meaning an electric field and magnetic field travel together, oscillating at specific frequency. All metals are electrical conductors and all metals are also opaque to light. Why might this be, knowing the nature of light waves?

A) The electric field of the wave excites electrons, which move through the solid conductor and dissipate the electric field, stopping the light wave.
B) The metal atoms absorb the light into their nucleus.
C) The free electrons in the metal capture the light.
D) The magnetic field polarizes iron, so all metals have a similar property, so when the magnetic field interacts with atoms, it dissipates the wave.

Accepted Answer

The answer of Light is an electromagnetic wave, meaning an...

Question 14

The old fashioned incandescent light bulb produces yellowish colored light by heating tungsten to a very high temperature and the tungsten radiates light peaking in the yellowish- white range. If you wanted a more blue light that was brighter, what would you need to do with a simple filament light bulb?

A) You couldn't do this; it isn't possible.
B) You would have to add more electrical current to raise the filament to a higher temperature, which would make it burn out faster.
C) You would have to add a layer of some other material that would absorb the longer wavelengths of light.
D) You would have to make the filament thicker and add more current to make it glow brighter for example, a 75w vs 40w bulb..

Accepted Answer

The answer of The old fashioned incandescent light bulb produces...

Question 15

A microwave oven is a good example of a familiar device that relies on absorption of electromagnetic waves at fixed frequencies by specific elements or compounds. In this case, water absorbs strongly in the microwave band used by the device, heating water molecules in food. What might a microwave oven imply about measuring microwaves emitted by the Sun on Earth?

A) Microwave radiation will be heavily absorbed in the earth's atmosphere, particular if humidity is high.
B) It is irrelevant; the Sun does not emit microwaves.
C) Microwaves will never make it to Earth because they will get absorbed by hydrogen between Earth and the Sun.
D) Microwaves must be the major reason for global warming.

Accepted Answer

The answer of A microwave oven is a good example...

Question 16

You take a block of granite and heat it to 1000 degrees Kelvin, and it glows bright red. If you then heat it to 1200 Kelvin, how might it look different?&#10;A) It would be about the same brightness but white.&#10;B) It would be much brighter and red.&#10;C) It would be brighter and more white.&#10;D) None of the above; it would have melted, and once it melts, it will no longer emit.&#10;

Accepted Answer

The answer of You take a block of granite and...

Question 17

Consider the following image of the Orion nebula   The Orion nebula is an___________ nebula.&#10;A) reflection&#10;B) electromagnetic&#10;C) dark&#10;D) emission&#10;

Accepted Answer

The answer of Consider the following image of the Orion...

Question 18

Which of the following colors has the longest wavelength?&#10;A) green&#10;B) orange&#10;C) red&#10;D) violet&#10;E) blue&#10;

Accepted Answer

The answer of Which of the following colors has the...

Question 19

Which of the following is not considered a form of electromagnetic radiation? A) gamma rays B) X- rays C) visible light D) gravity E) radio waves

Accepted Answer

The answer of Which of the following is not considered...

Question 20

Visible light is a small part of the electromagnetic spectrum, but when we see colors, we are seeing___________ .&#10;A) different photons that come from different directions&#10;B) refractions of white light&#10;C) complementary spectra from light re- emitted off objects when light impinges on the object&#10;D) an even narrow range of wavelengths than white light within the visible light spectrum&#10;

Accepted Answer

The answer of Visible light is a small part of...

Question 21

Because lenses act like a prism to separate the colors of the spectrum, they produce a troublesome effect known as ___________.&#10;A) the atmospheric effect&#10;B) chromatic aberration&#10;C) focal distortion&#10;D) light dispersion&#10;E) poor seeing&#10;

Accepted Answer

The answer of Because lenses act like a prism to...

Question 22

The Spitzer space telescope is ___________.&#10;A) a planned replacement telescope for Hubble&#10;B) a thermal infrared detecting telescope&#10;C) the next generation gamma ray detecting satellite&#10;D) a new X- ray detecting observatory&#10;

Accepted Answer

The answer of The Spitzer space telescope is ___________.&#10;A) a...

Question 23

The layer of the solar atmosphere directly above the photosphere is referred to as the ___________.&#10;A) megasphere&#10;B) corona&#10;C) chromosphere&#10;D) solarsphere&#10;E) ionosphere&#10;

Accepted Answer

The answer of The layer of the solar atmosphere directly...

Question 24

What is the ideal way, if cost is no object, for a telescope to avoid atmospheric disturbance?&#10;A) Place it in a very dry climate, like the deserts in Chile.&#10;B) Place it in space.&#10;C) Place it on land, as far from the ocean as possible.&#10;D) Place it on a very high mountain.&#10;

Accepted Answer

The answer of What is the ideal way, if cost...

Question 25

To improve the resolution of radio telescopes, astronomers___________ .&#10;A) make bigger telescopes&#10;B) group smaller telescopes in arrays, like the very large array in New Mexico&#10;C) scan the skies rapidly to detect the direction of the radio signal&#10;D) place the telescope in outer space&#10;

Accepted Answer

The answer of To improve the resolution of radio telescopes,...

Question 26

The first telescopes, and most amateur telescopes, rely on the human eye to observe objects. The first improvement on this observation method used___________ .&#10;A) projection systems&#10;B) photographic film&#10;C) digital cameras&#10;D) polyspectral scanners&#10;

Accepted Answer

The answer of The first telescopes, and most amateur telescopes,...

Question 27

In a radio telescope, the electromagnetic energy is gathered by ___________.&#10;A) a spherical thin metal foil that refracts the radio waves to a point&#10;B) a parabolic metallic mirror, commonly wire mesh&#10;C) a solid slab or copper metal, formed into the shape of a parabola&#10;D) a glass mirror with a reflective coating, similar to an optical telescope&#10;

Accepted Answer

The answer of In a radio telescope, the electromagnetic energy...

Question 28

Which of the following is not a discovery made by the Hubble Space Telescope? A) distinction of the various rings of Saturn B) deep space images never seen before C) evidence for massive black holes in the center of our galaxy D) demonstration that disk shaped dust clouds are common around young stars

Accepted Answer

The answer of Which of the following is not a...

Question 29

The first telescopes, and most amateur telescopes, rely on the human eye to observe objects. Modern telescopes record the observations with___________ .&#10;A) photographic film&#10;B) polyspectral scanners&#10;C) digital cameras&#10;D) projection systems&#10;

Accepted Answer

The answer of The first telescopes, and most amateur telescopes,...

Question 30

Which one of these types of telescopes uses gamma rays for observation?&#10;A) Swift&#10;B) Spect- R&#10;C) Planck&#10;D) Chandra&#10;

Accepted Answer

The answer of Which one of these types of telescopes...

Question 31

The problems encountered with lenses caused this scientist to build reflecting telescopes of his own design.&#10;A) Sir Isaac Newton&#10;B) George Hale&#10;C) Niels Bohr&#10;D) Galileo&#10;E) Albert Einstein&#10;

Accepted Answer

The answer of The problems encountered with lenses caused this...

Question 32

The outermost layer of the Sun is called the ___________.&#10;A) ionosphere&#10;B) chromosphere&#10;C) megasphere&#10;D) corona&#10;E) photosphere&#10;

Accepted Answer

The answer of The outermost layer of the Sun is...

Question 33

Which of the following types of telescopes use lenses similar to that of ordinary eyeglasses?&#10;A) adaptive&#10;B) orbital&#10;C) refracting&#10;D) reflective&#10;

Accepted Answer

The answer of Which of the following types of telescopes...

Question 34

Nearly all large optical telescopes built today are___________ .&#10;A) radio&#10;B) refractors&#10;C) reflectors&#10;

Accepted Answer

The answer of Nearly all large optical telescopes built today...

Question 35

Which of the following is not an advantage that radio telescopes have over optical telescopes? A) They can operate 24 hours a day. B) They are less affected by the conditions of the atmosphere. C) They are generally less expensive. D) They have better resolution. E) They can "see" through interstellar dust clouds.

Accepted Answer

The answer of Which of the following is not an...

Question 36

Why would astronomers place an X- ray observatory in space, like the Chandra observatory?&#10;A) to record X- rays emitted from the big bang; the so called background radiation of the universe&#10;B) to map deep X- ray emissions from deep space, particularly as a proxy for materials being sucked into black holes&#10;C) to map X- ray emissions from the moon&#10;D) to map X- ray emissions from the sun&#10;

Accepted Answer

The answer of Why would astronomers place an X- ray...

Question 37

How do modern telescopes prevent problems of earlier telescopes that limited mirror size and stability during temperature changes?&#10;A) They only use telescopes in space to avoid the atmosphere.&#10;B) They use a digital imaging system and process the image to remove distortions.&#10;C) They use a mirror that is constantly adjusted in shape to adjust for changes in atmospheric distortions.&#10;D) They use a super refraction system that uses a series of small lenses that avoid chromatic effects to collect more light than previously possible.&#10;

Accepted Answer

The answer of How do modern telescopes prevent problems of...

Question 38

The layer of the Sun that radiates most of the light that reaches Earth is called the___________ .&#10;A) corona&#10;B) chromosphere&#10;C) megasphere&#10;D) photosphere&#10;E) ionosphere&#10;

Accepted Answer

The answer of The layer of the Sun that radiates...

Question 39

Classic Newtonian reflector telescopes use a mirror shaped like ___________.&#10;A) a concave spherical surface&#10;B) a hyperbola&#10;C) a parabola&#10;D) a convex spherical surface&#10;

Accepted Answer

The answer of Classic Newtonian reflector telescopes use a mirror...

Question 40

Why would astronomers be interested in placing a gamma ray detecting observatory in space?&#10;A) to map high- energy electromagnetic waves from distant sources that would be blocked out or scattered by Earth's atmosphere&#10;B) to map gamma ray emissions from radioactive elements on Earth&#10;C) to map gamma ray emissions coming from the Sun&#10;D) to detect nuclear weapons tests on Earth&#10;

Accepted Answer

The answer of Why would astronomers be interested in placing...

Question 41

There are websites that predict solar weather, or essentially the impact of the solar wind on earth. How is this possible when the speed of light is a fixed quantity? A) The solar weather effect on Earth depends largely on the earth's magnetic field and its interaction with Earth weather, so scientists predict variations in both. B) The solar forecast is like weather forecasting on Earth; solar scientists observe phenomena as they form and grow on the sun, and predict their timing. C) The solar wind does not travel at the speed of light, so it arrives much later than when a solar event is observed. D) The solar weather is related to sunspots, and they only affect Earth when the sunspots are in line with the earth, so knowing the solar rotation speed, you can predict when sunspots are aimed at Earth.

Accepted Answer

The answer of There are websites that predict solar weather,...

Question 42

The most conspicuous features on the surface of the Sun are dark areas called___________ .&#10;A) granules&#10;B) helium lines&#10;C) flares&#10;D) sunspots&#10;E) spicules&#10;

Accepted Answer

The answer of The most conspicuous features on the surface...

Question 43

How do astronomers save their eyes when looking at the Sun through a telescope?&#10;A) They use heavy filters to block out light, particularly at specific wavelengths.&#10;B) They use a special water cooled camera system to avoid superheating the camera.&#10;C) They project the telescope image onto a large screen or record the image with a camera.&#10;D) They look at the image very quickly.&#10;

Accepted Answer

The answer of How do astronomers save their eyes when...

Question 44

If you live at high latitude, when do you expect to see the aurora? A) at times of high sunspot activity, during the active sun B) during low sun spot activity, when solar flares are most abundant C) at times when the earth's magnetic field has temporarily been weakened D) at intermediate periods when sunspots are present but not prominent

Accepted Answer

The answer of If you live at high latitude, when...

Question 45

The Sun produces energy by converting___________ .&#10;A) oxygen nuclei to carbon dioxide&#10;B) carbon monoxide to oxygen nuclei&#10;C) oxygen nuclei to nitrogen nuclei&#10;D) helium nuclei to hydrogen nuclei&#10;E) hydrogen nuclei to helium nuclei&#10;

Accepted Answer

The answer of The Sun produces energy by converting___________ .&#10;A)...

Question 46

The most explosive events to occur on the Sun are ___________.&#10;A) solar winds&#10;B) filaments&#10;C) solar flares&#10;D) umbras&#10;E) sunspots&#10;

Accepted Answer

The answer of The most explosive events to occur on...

Question 47

During periods of high solar activity, huge cloudlike structures that appear as great arches extending from the Sun are often produced. These solar features are called___________ .&#10;A) spicules&#10;B) prominences&#10;C) plages&#10;D) quasars&#10;E) the solar wind&#10;

Accepted Answer

The answer of During periods of high solar activity, huge...

Question 48

The solar wind originates from ___________.&#10;A) the interior of the Sun&#10;B) the corona&#10;C) the photosphere&#10;D) the heliosphere&#10;

Accepted Answer

The answer of The solar wind originates from ___________.&#10;A) the...

Question 49

What does Einstein's formula e = mc²have to do with the Sun? A) It relates to how much energy is carried away from the Sun when mass is ejected from the Sun at the speed c. B) It determines the energy released when 4 protons are fused to make a helium atom in the interior of the Sun. C) It determines the energy released as the solar mass is converted to energy as matter is intensely compressed in its interior. D) The formula has nothing to do with the Sun.

Accepted Answer

The answer of What does Einstein's formula e = mc^2...

Question 50

The amount of energy released during a nuclear reaction was determined by___________ .&#10;A) Sir Isaac Newton&#10;B) Albert Einstein&#10;C) Galileo&#10;D) Niels Bohr&#10;E) George Hale&#10;

Accepted Answer

The answer of The amount of energy released during a...

Question 51

The source of the Sun's energy is ___________.&#10;A) nuclear fusion&#10;B) heat of contraction&#10;C) potential energy&#10;D) chemical burning&#10;E) nuclear fission&#10;

Accepted Answer

The answer of The source of the Sun's energy is...

Question 52

The frequency of sunspots and related solar activity is___________ . A) an 11 year cycle B) a 7 year cycle C) a 22 year cycle D) not a regular cycle

Accepted Answer

The answer of The frequency of sunspots and related solar...

Question 53

The corona is about ___________degrees Kelvin.&#10;A) 150&#10;B) 273,000&#10;C) 10,000&#10;D) 1 million&#10;

Accepted Answer

The answer of The corona is about ___________degrees Kelvin.&#10;A) 150&#10;B)...

Question 54

If solar flares pose a danger to orbiting spacecraft and astronauts, how much warning is there for the danger?&#10;A) The danger is primarily from emission of neutrinos, which move at just below the speed of light; hence the warning is only a few seconds after a feature is observed.&#10;B) There is no warning; the radiation arrives at the same time as the feature is observed because they all travel at the speed of light.&#10;C) The primary danger is from high energy particles that travel at the speed of the solar wind 500km/s, so there is ample warning of 3- 5 days.&#10;D) The danger is from high energy particles moving thousands of km per second, so the warning is a few hours.&#10;

Accepted Answer

The answer of If solar flares pose a danger to...

Question 55

Hydrogen &#34;burning&#34; in stars is ___________.&#10;A) an atomic reaction that fuses 4 protons to make a helium nucleus, releasing energy by converting mass to energy&#10;B) an atomic reaction that generates hydrogen by splitting helium atoms&#10;C) hydrogen atoms that combine with deuterium atoms to make HD complexes, and this reaction generates immense amounts of energy&#10;D) a chemical reaction that bonds hydrogen to oxygen to make water, which remains a gas because of the extremely high temperatures&#10;

Accepted Answer

The answer of Hydrogen &#34;burning&#34; in stars is ___________.&#10;A) an...

Question 56

Hale discovered that sunspots were associated with magnetic fields. What happens to these magnetic fields during a full sunspot cycle?&#10;A) They change polarity.&#10;B) They get weaker.&#10;C) They die away.&#10;D) They get stronger.&#10;

Accepted Answer

The answer of Hale discovered that sunspots were associated with...

Question 57

The part of the Sun clearly visible during a solar eclipse is ___________.&#10;A) the corona&#10;B) the photosphere&#10;C) the mesosphere&#10;D) the chromospheres&#10;

Accepted Answer

The answer of The part of the Sun clearly visible...

Question 58

Irregularities in brightness on the Sun's photosphere granules. are produced by___________ .&#10;A) different elemental abundances being stirred within the photosphere, to produce variable brightness&#10;B) large convective cells within the photosphere&#10;C) local violent explosions within the photosphere equivalent to a hydrogen bomb explosion&#10;D) pods of solid mass ejected to the photosphere by violent explosions within the Sun's interior, hence the name granule&#10;

Accepted Answer

The answer of Irregularities in brightness on the Sun's photosphere...

Question 59

Streams of protons and electrons emitted from the Sun produce___________ .&#10;A) prominences&#10;B) quasars&#10;C) granules&#10;D) plages&#10;E) the solar wind&#10;

Accepted Answer

The answer of Streams of protons and electrons emitted from...

Question 60

Prominences and solar flares present dangers to astronauts primarily because___________ . A) they do not pose a danger to astronauts B) they disrupt communications on Earth C) they pose a radiation danger from X- rays and gamma rays, but primarily from high- energy particle emissions D) they can overheat the spacecraft

Accepted Answer

The answer of Prominences and solar flares present dangers to...

Question 61

All of the world's largest telescopes are of the___________ type.&#10;A) radio&#10;B) reflecting&#10;C) optical&#10;D) refracting&#10;

Accepted Answer

The answer of All of the world's largest telescopes are...

Question 62

In the case of light, when a source is moving away, its light appears ___________than it actually is.&#10;A) redder&#10;B) bluer&#10;C) whiter&#10;D) greener&#10;

Accepted Answer

The answer of In the case of light, when a...

Question 63

Astronomers currently estimate sunspots to be about___________ degrees cooler than the rest of the surface.&#10;A) 1500&#10;B) 2500&#10;C) 1000&#10;D) 500&#10;

Accepted Answer

The answer of Astronomers currently estimate sunspots to be about___________...

Question 64

The wavelength of___________ is longer than the wavelength of yellow light.&#10;A) green&#10;B) violet&#10;C) red&#10;D) blue&#10;

Accepted Answer

The answer of The wavelength of___________ is longer than the...

Deck 23: Light, Telescopes, and the Sun