Welcome to the PAC Astronomy Trivia Page!

Each day a new Trivia question, along with it’s answer, is posted to provide unique and interesting astronomical related facts.

We hope these trivia items inspire folks to learn something new and interesting everyday, while expanding their knowledge of the Universe.

If you have a special trivia item you would like posted contact the webmaster at or call (928) 778-6502.

July 25, 2017 (00327)
When was the first astrophotograph taken and by who?
On January 2nd, in 1839 – the first ever photo of the moon was taken.  It was taken by a French Photographer named Louis Daguerre.   Louis Daguerre had become famous in 1822 when he invented the Diorama. His Moon photo is believed to be the very first astronomy photograph in history!


July 24, 2017 (00326)
What is the history of the telescope?
The earliest known telescope
appeared in 1608 in the Netherlands when an eyeglass maker named Hans Lippershey tried to obtain a patent on one. Although Lippershey did not receive his patent, news of the new invention soon spread across Europe. The design of these early refracting telescopes consisted of a convex objective lens and a concave eyepiece. Galileo improved on this design the following year and applied it to astronomy. In 1611, Johannes Kepler described how a far more useful telescope could be made with a convex objective lens and a convex eyepiece lens and by 1655 astronomers such as Christiaan Huygens were building powerful but unwieldy Keplerian telescopes with compound eyepieces.

Isaac Newton is credited with building the first reflector in 1668 with a design that incorporated a small flat diagonal mirror to reflect the light to an eyepiece mounted on the side of the telescope. Laurent Cassegrain in 1672 described the design of a reflector with a small convex secondary mirror to reflect light through a central hole in the main mirror.

July 23, 2017 (00325)
Is the Universe a sphere? If not, which shape it is? How do we know that?
1. The “Observable Universe” is a spherical region of space centered around the observer in question, with a radius that is currently about 46 billion light-years.

2. The entire Universe may or may not be infinite, and there are three options for its over-all “shape” (two of which are infinite, one of which is not). Our current measurements are consistent with any of the three options, but even if the Universe is finite, it is much much bigger than the part we can see.

July 22, 2017 (00324)
What old is the Sun
Approximately 4.6 billion years ago?

July 21, 2017 (00323)
Who was Karl Schwarschild?
ANSWER:  The characteristics of an event horizon were first worked out by astronomer and mathematician Karl Schwarzschild. A member of the German army in World War I, he died in 1916 of an illness he contracted while doing artillery shell calculations on the Russian front. His paper on the theory of event horizons was among the last things he finished as he was dying; it was the first exact solution to Einstein’s equations of
general relativity. The radius of the event horizon is called the Schwarzschild radius in his memory.
REFERENCE: Welcome to Astronomy, an OpenStax resource, page 868.
“Download for free at

July 20, 2017 (00322)
How fast is the relative speed that Earth experiences as it orbits the Sun?
ANSWER: Approximately 66,000 mph.
REFERENCE: Welcome to Astronomy, an OpenStax resource, page 20.
“Download for free at

July 19, 2017 (00321)
What were fixed stars?
Originally stars in general, which, until the early 18th century and the discovery of Proper Motion, were thought to have no relative motion and thus remained fixed in position in the sky. In comparison, the planets were described as wandering stars (from the Greek planetes, a wanderer).

REFERENCE: The Facts on File Dictionary of Astronomy, Fifth Edition

July 18, 2017 (00320)
What was John Deutschendorf, Jr. and what song did he write after seeing the Perseids Meteor shower on a camping trip to Colorado?
ANSWER: John Denver, Rocky Mountain High

July 17, 2017 (00319)
What is an Annular Solar Eclipse?
ANSWER: An annular solar eclipse occurs when the Moon appears smaller than the Sun as it passes centrally across the solar disk and a bright ring, or annulus, of sunlight remains visible during the eclipse.

July 16, 2017 (00318)
What is a Total Eclipse
ANSWER: A total solar eclipse occurs when the Moon completely covers the Sun, as seen from Earth.

July 15, 2017 (00317)
What is a Partial Eclipse ?
ANSWER: A partial solar eclipse happens when the Moon only partially covers the disk of the Sun.

July 14, 2017 (000316)
Where are the Voyagers?
ANSWER: Check out the real-time information on these space craft!

July 13, 2017 (000315)
How fast are YOU spinning on Earth’s axis right now?
Between 0 and 1040 mph.


July 12, 2017 (000314)
What is a Kiva?
A Native American underground ceremonial chamber, partically open at the top.  Associated with various rituals, many are clearly oriented to the Sun.

REFERENCE: The Complete Idiot’s Guide to Astronomy

What is albation?

The loss of material from the surface of a moving body as a result of vaporization, friction, etc.
REFERENCE: The Facts on File Dictionary of Astronomy, Third Edition

July 10, 2017 (000312)
What is a Yellow Dwarf?
A yellow dwarf is a star and is often referred to as a G-type main sequence star. A perfect example of a yellow dwarf would be the Sun. A yellow dwarf has a mass almost like the mass of the sun. Its color ranges from white to a lighter yellow. Among the stars in the galaxy, yellow dwarf stars are bigger than most of the stars although giant stars are the biggest of all.


July 9, 2017 (000311)
What is A Planemo?
A planemo is a celestial object of planetary mass – one that is larger than an irregularly shaped asteroid, yet smaller than a nuclear reactive star. The term covers all bodies within this size range, although a planemo that orbits a star is more regularly referred to with the more specific term,
planet. Planemo is a contraction of planetary mass object.

July 8, 2017 (000310)
What is a Magnetar?
A magnetar is a type of
neutron star with an extremely powerful magnetic field. The magnetic field decay powers the emission of highenergy electromagnetic radiation, particularly X-rays and gamma rays.

July 7, 2017 (000309)
What is nadar?
The point directly below you.

July 6, 2017 (000308)
What was NASA’s first spacecraft to scan another planet?
Fifty-five years ago on Aug. 27, 1962, Mariner 2 was launched on a mission to scan Venus, becoming NASA’s first spacecraft to scan another planet.

July 5, 2017 (000307)
What single factor determines a star’s brightness, color, length of its life, and how it is to die?
It’s total mass.

July 4, 2017 (000306)
What is the largest known comet to date?
There are different ways to measure a comet. The Hale Bopp Comet, for example has a nucleus of more than 60 miles in diameter, which is thought to be the biggest ever encountered, so far. And Comet Hyakutake’s tail stretched out at a distance of more than 500 million km from the nucleus, the largest known. But now a group of scientists have identified a new category of measuring a comet’s size: the region of space disturbed by the comet’s presence. And for this class, first prize goes to Comet C/2006 P1 McNaught, which graced our skies in Janauary and February 2007. Of course, McNaught might win the prize for most picturesque comet, too, as this stunning image from Sebastian Deiries of ESO shows.

Dr. Geraint Jones of University College, London and his team used 2007 data from the now-inoperable Ulysses spacecraft, which was able to gauge the size of the region of space disturbed by the comet’s presence.

Ulysses encountered McNaught’s tail of ionized gas at a distance downstream of the comet’s nucleus more than 225 million kilometers. This is far beyond the spectacular dust tail that was visible from Earth in 2007.

“It was very difficult to observe Comet McNaught’s plasma tail remotely in comparison with the bright dust tail,” said Jones, “so we can’t really estimate how long it might be. What we can say is that Ulysses took just 2.5 days to traverse the shocked solar wind surrounding Comet Hyakutake, compared to an incredible 18 days in shocked wind surrounding Comet McNaught. This shows that the comet was not only spectacular from the ground; it was a truly immense obstacle to the solar wind.”

A comparison with crossing times for other comet encounters demonstrates the huge scale of Comet McNaught. The Giotto spacecraft’s encounter with Comet Grigg-Skjellerup in 1992 took less than an hour from one shock crossing to another; to cross the shocked region at Comet Halley took a few hours.

“The scale of an active comet depends on the level of outgassing rather than the size of the nucleus,” said Jones. “Comet nuclei aren’t necessarily active over their entire surfaces; what we can say is that McNaught’s level of gas production was clearly much higher than that of Hyakutake.”

Jones presented his findings at the RAS National Astronomy Meeting in Glasgow, Scotland.

July 3, 2017 (000305)
What is Hubble’s Law?
The law of physics that states that the farther a galaxy is from us, the faster it is moving away from us.

July 2, 2017 (000304)
What was the Cosmic String?
A tube-like configuration of energy that is believed to have existed in the early universe. A cosmic string would have a thickness smaller than a trillionth of an inch but its length would extend from one end of the visible universe to the other.

July 1, 2017 (000303)
Is there life on the moon today?
Could be!  We know cockroaches can survive in space because an Apollo mission noticed one inside their space craft. When it returned, the craft was thoroughly inspected and no trace of the cockroach was found. The conclusion was that it crawled out while they were on the moon. The question is, “Did it survive?”

June 30, 2017 (000302)
What is the width of the totality path of the 2017 Solar Eclipse?
The path for this eclipse is projected at 60-70 miles wide. The closer you are to the center of the path, the longer totality lasts.
NASA has an interactive map that allows users to receive site-specific eclipse details.

June 29, 2017 (000301)
What phenomenon causes the Moon’s rotation about it’s own axis
to be equal to the Moon’s period of revolution about the Earth?
Tidal Friction.

June 28, 2017 (000300)
What causes a planet to have a magnetic field?
The dynamo effect.

June 27, 2017 (000000299)
Why are Mercury and Venus referred to as inferior planets?
Because their orbits are inside the Earth’s orbit.

June 26, 2017 (000298)
Whereas latitude and longitude are the coordinates of places on earth, what are the two coordinates used for star locations?
Right ascension and Declination.

June 25, 2017 (000297)
What is the name given to the configuration when three celestial bodies are in a line?

June 24, 2017 (000296)
Who wrote the book “On the Revolutions of the Heavenly Spheres”?

June 23, 2017 (000295)
A comet’s tail points in which direction?
Away from the Sun.

June 22, 2017 (000294)
Where in space is Cassini’s division?
Between two rings of Saturn.

June 21, 2017 (000293)
What is our Sun’s sunspot cycle?
11 Years.

June 20, 2017 (000292)
What are the processes currently recognized as causing the Van Allen Radiation Belt?
 It is generally understood that the inner and outer Van Allen belts result from different processes. The inner belt, consisting mainly of energetic protons, is the product of the decay of so-called
albedoneutrons which are themselves the result of cosmic ray collisions in the upper atmosphere. The outer belt consists mainly of electrons. They are injected from the geomagnetic tail following geomagnetic storms, and are subsequently energized through wave-particle interactions.

June 19, 2017 (000291)
What is the faster spacecraft ever?
After a five-year jaunt through space,
NASA’s robotic Juno spacecraft arrived at Jupiter on July 4, 2016, and the gas giant’s impressive gravity accelerated the probe to approximately 165,000 mph (265,000 km/h) relative to Earth. This made Juno the fastest-moving human-made object in history.

June 18, 2017 (000290)
How many people have walked on the moon?
In total twelve people have walked on the Moon. Besides Neil Armstrong and Buzz Aldrin – who were the first two astronauts to leave their bootprints on the Moon — there were also Pete Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Eugene Cernan, and Harrison Schmitt.

June 17, 2017 (000289)
What evidence supports the existence of Dark Energy?
The evidence for dark energy is indirect but comes from three independent sources: (1) Distance measurements and their relation to redshift, which suggest the universe has expanded more in the last half of its life.

(2) The theoretical need for a type of additional energy that is not matter or dark matter to form the observationally flat universe (absence of any detectable global curvature).
(3) It can be inferred from measures of large scale wave-patterns of mass density in the universe.

June 16, 2017 (000288)
How much does the earth weigh?
5.9736 x 1024 kg or 5,973,600,000,000,000,000,000,000 kg or 5.9 sextillion tonnes
Earth’s mass constantly changes. For example, it gains an estimated 40,000 tons each year due to cosmic dust such as meteors and dust comets. It loses about 95,000 tons per year due to atmospheric escape of gasses.

June 15, 2017 (000287)
What is the largest and most massive object in the Kuiper Belt??


June 14, 2017 (000286)
What percentage of the universe is composed of visible matter?
Approximately 4%.


June 13, 2017 (000285)
What is the Ponzo illusion?
The Ponzo illusion is one possible explanation of the
Moon illusion, with objects appearing “far away” (because they are “on” the horizon) appearing bigger than objects “overhead”.

June 12, 2017 (000284)
What is the speed of darkness?

June 11, 2017 (000283)
As of March 2016, what is the farthest observed galaxy?
(Article) (Article)

June 10, 2017 (000282)
What is an Axion?
A hypothetical subatomic particle of low mass and energy that is postulated to exist because of certain properties of the strong force.
(Article) (Article)

June 9, 2017 (000281)
What is a parsec?
A parsec is a unit of length used in astronomy, approximately equal to 3.261 light years.

June 8, 2017 (00027)
How does the sun burn?  Is there oxygen in space?   Isn’t that needed for fire?
The burning in a fire is a chemical reaction, requiring oxygen. If such a chemical reaction were responsible for the heat of the Sun, the Sun would have lasted for less than 100 million years. We know, however, that the Sun must be several billion years old. Therefore, a greater source of energy is required.

We now know that the Sun is powered by nuclear fusion reactions taking place at the center of the glowing ball of gas that we observe from the Earth. Unlike the Earth’s atmosphere, most of the gas in the universe is hydrogen. The Sun’s energy primarily comes from the fusion of hydrogen into helium. The glow we see from the Sun’s surface is from gas that is kept hot by heat from these fusion reactions at the Sun’s center. The temperature of the gas at the surface of the Sun is about 6000 degrees. The temperature at the center of the Sun is 16 million degrees!

So, although the Sun is very hot, there is no fire in or on the Sun in the sense of a chemical wood fire or candle flame here on Earth that requires oxygen to burn.

The amount of oxygen in space is tiny compared to the amount of hydrogen (more than 1000 hydrogen atoms for each atom of oxygen). Nevertheless, oxygen is still the third-most abundant element and was necessary for the water and, ultimately, life on Earth. The precise amount of oxygen in the Sun is currently being debated and revised, and this has important consequences for the precise modeling of the Sun’s interior.

June 7, 2017 (00026)
What is the velocity of plasma from a solar flare as it heads toward Earth?
An important point needs to be made before answering this question. Geomagnetic storms are observed to be primarily if not entirely associated with large ejections of mass from the Sun called coronal mass ejections. Coronal mass ejections (CMEs) were originally thought to be driven by solar flares. It is now known that many CMEs occur without any observable flare associated with them. Likewise, many flares occur for which no associated CME is observed. Therefore, phenomena associated with geomagnetic storms such as power grid failures, many satellite failures, and the aurora are most closely associated with CMEs rather than flares. On the other hand, interruptions in radio communications and expansion of the Earth’s atmosphere, resulting in increased drag on satellites in low Earth orbit, are associated with radiation from flares. The electromagnetic radiation from flares travels at the speed of light and reaches the Earth in eight minutes. CMEs, on the other hand, travel at speeds from 100 to 1000 kilometers per second and take several days to reach the Earth. The relative importance of studying CMEs versus flares for the purpose of predicting many phenomena at the Earth is presently a subject of much controversy.

June 6, 2017 (00025)
What special precautions are taken aboard the space shuttle to prevent damage to their electronic components and how are the astronauts protected?
The primary protection is the Shuttle orbit. The altitude of the Shuttle is typically 300-500 km (200-300 miles) above sea level. This is well within the Earth’s magnetic field (the “magnetosphere”) and below the Earth’s radiation belts (the van Allen belts). This magnetic field protects us from most of the charged particles from space, including from the Sun. Since these charged particles can travel along the Earth’s magnetic field to lower altitudes at the poles, however, the Shuttle orbit also avoids the regions around the north and south poles. (Enhanced fluxes of charged particles around the poles are responsible for the beautiful auroral displays visible at high latitudes). Manned missions to the Moon or Mars are much more dangerous, since these require leaving the protection of the Earth’s magnetic field.

Some high-energy charged particles (“cosmic rays”) do penetrate down to the Shuttle orbit and to the surface of the Earth. Collisions with the Earth’s atmosphere stops most of these particles. The flux of these particles is higher at the Shuttle, however, since its orbit is above much of the atmosphere. Therefore, the risk of damage is higher at the Shuttle orbit than at the surface of the Earth. The Shuttle shroud does provide protection, but not from the highest energy particles. The Shuttle astronauts have in fact seen flashes resulting from the interaction of high-energy protons with their eyes. Nevertheless, the increased health risk is not unacceptably high.

June 5, 2017 (00024)
hat is the duration of a solar flare – minutes? hours? days?
The duration of a solar flare in the energetic hard x-rays is seconds to minutes (this is called the impulsive phase of the flare). The evolution of the less energetic soft x-rays from a flare is more gradual. This emission can last from minutes to hours.

June 4, 2017 (00023)
Who was the first US woman in space?
The first American Women in space was Sally Ride.  She flew on STS-7, which launched on June 18, 1983.


June 3, 2017 (00022)
Who made the first space walk? ?
Ed White made the United States’ first spacewalk on 3 June 1965 during the Gemini 4 mission.


June 2, 2017 (00021)
What are constellations?
A constellation is formally defined as a region of the celestial sphere, with boundaries laid down by the International Astronomical Union (IAU). The constellation areas mostly had their origins in Western-traditional patterns of stars from which the constellations take their names.


June 1, 2017 (00020)
Where on Earth can you see all the stars withing a 24 hour period?
On the equator.

May 31, 2017 (00019)
What is zenith?
The point directly above you when looking up at the sky.

May 30, 2017 (00018)
What is the definition of the word astronomy?
Astronomy (from the Greek ἀστρονομία from ἄστρον astron, “star” and -νομία -nomia from νόμος nomos, “law” or “culture”) means “law of the stars” (or “culture of the stars” depending on the translation).

May 29, 2017 (00017)
What causes gravitational waves and when were they first discovered?
About 1.3 billion years ago (back when the first plants were showing up on Earth’s surface), two black holes collided in a titanic event. They eventually merged to become one very massive black hole with the mass of about 62 suns. It was an unimaginable event and created ripples in the fabric of space-time. They showed up as gravitational waves, first detected in 2015, by the Laser Interferometer Gravitational Wave Observatory (LIGOobservatories in Hanford, WA and Livingston, LA.

May 28, 2017 (00016)
What will Osiris-REX Discover at Asteroid Bennu?
The hope is that Bennu will tell us about life in both a cosmic and literal sense. An ancient and pristine object, Bennu is like a time capsule, preserving the conditions of the early Solar System when all the planets formed. The asteroid is also loaded with carbon, an essential element for life as we know it, so studying Bennu could teach us more about the origin of Earth’s flora and fauna.

May 27, 2017 (00015)
If our entire solar system could fit into a coffee cup, how big would our galaxy be (The Milky Way)?
The North American Continent

May 26, 2017 (00014)
The precise position of the Sun at noon each day changes over a period of a year, describing a “figure 8” in the sky. What is this called?
ANSWER: The Analemma
(Article)March 29, 2017 (00013)
How are Magnifcation and Focal Ratios determined?

May 25, 2018 (00012)
What is collimation and how is it accomplished?


May 24, 2017 (00011)
What did the Earth do in 1910 that caused unnecessary fear for many people around the world?
Passed through Halley’s Comet tail.

May 23, 2017 (00010)
Just after New Moon, we can faintly see the part of the Moon that is still in shadow.
What famous person is the first one known to recognize that this is from “earthshine” (sunlight reflected off the Earth, to the Moon, and back)?

Leonardo da Vinci

May 22, 2017 (00009)
When there are two full moons in the same calendar month the second one is called a “Blue Moon.”
How often does this event happen on average?
2 1/2 to 3 Years

May 21, 2017 (00008)
What is the name of the most prominent crater on the Moon?
Answer: Tycho

May 20, 2017 (00007)
In 1609 Galileo discovered four moons orbiting Jupiter. Three of them are named “Io”, “Ganymede” and “Callisto.”
What did he name the other one?

Answer: Europa

May 19, 2017 (00006)
What color is on the outside of the arc of a rainbow?
Answer: Red

May 18, 2017 (00005)
If the Universe Is Expanding, Why Are the Milky Way and Andromeda Galaxies on a Collision Course?

To get to the answer, we will need to look at which forces operate on small and large astronomical scales (distances). The two fundamental forces at play in this case are gravity and dark energy. Gravity is certainly the more familiar of the two, so let’s start there…


May 17, 2017 (00004)
In 4-5 billion years the Sun is forecast to expand enough to engulf the earth.  How fast is the Sun currently expanding each day?
Right now (and for the past 5 billion years or so, and for the next 4-5 billion years) the sun is pretty much in equilibrium — the tremendous pull of gravity due to its mass is balanced by the outflow of energy from nuclear fusion. It’s size changes a tiny, tiny fraction now and then, but this is an in-and-out type of motion, almost like respiration, as the two forces mentioned above fight to stay in balance.

May 16, 2017 (00003)
What is the Antikythera mechanism?
The Antikythera mechanism is an ancient analogue computer and orrery used to predict astronomical positions and eclipses for calendrical and astrological purposes, as well as the Olympiads, the cycles of the ancient Olympic Games.

May 15, 2017 (00002)
How did the Sun get its name?

The sun has had multiple names over the centuries, including the French word “soleil,” the Latin term “sol” from the ancient Romans and “helios” from the ancient Greeks. However, after Germany coined the term “sonne,” the word translated into English became “sonne” and later just “sun,” according to NASA.

May 14, 2017 (00001)
What is Planck time and how many units are in one second?

The Planck time is the length of time at which no smaller meaningful length can be validly measured due to the indeterminacy expressed in Werner Heisenberg‘s Uncertainty Principle. Theoretically, this is the shortest time measurement that is possible. Planck time is roughly 10−44 seconds. However, to date, the smallest time interval that was measured was 10−21 seconds. One Planck time is the time it would take a photon traveling at the speed of light to cross a distance equal to one Planck length.


Password Reset
Please enter your e-mail address. You will receive a new password via e-mail.