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biochemistry and biophysics

TRIVIA ARCHIVE: 2012 - 2013 - 2014 - 2015 - 2016


How does the pull of the Moon’s gravity affect Earth’s surface?

It creates tides.

The moon, along with the sun, exerts a gravitational pull on the Earth’s surface. The solid part of Earth may deform a bit, but water being fluid is more free to move.

Tides are the periodic changes in sea level with respect to land. The pull of the moon and sun, along with the centrifugal force created by the rotating Earth, cause water levels to rise and fall. The gravitational pull on water causes the oceans to bulge out in its direction.

We have two tides every day. Earth is spinning, the Moon travels around it, and together they travel around the sun. No wonder water can’t stand still.

The highest tides in the world are at the Bay of Fundy in Nova Scotia, Canada. Tides roll in and out, and difference in the height of the water has been as much as 53 feet.

Where is the moon larger โ€“ at the horizon or directly overhead?

The moon is always the same size.

Because the moon’s orbit is elliptical, there are times when it appears larger because it is closer, but on any given night, the Moon’s size remains constant.

The moon may look larger when it is closer to the horizon line and smaller when overhead, but this is an optical trick known as the Moon illusion.

The apparent size of the moon relates to our perception of distance. When the moon is near the horizon, we perceive it to be farther away from us than when it is directly overhead. Objects near the horizon line (buildings, trees, etc.) help reinforce the idea of the Moon’s inflated size because we know that it is behind those objects.

When it is above us, surrounded by empty space with no terrestrial reference points, it appears smaller. The same illusion applies to celestial bodies as well. Constellations may look larger the closer they are to the horizon. The stars, the Sun, and the Moon are identical in size no matter where they are in the sky.

Which is bigger: the Moon or Pluto?

The moon

Pluto used to be the smallest planet in our solar system, but in 1992 its planethood was questioned. In 2005, Eris which is 27% more massive than Pluto, was discovered. This finding prompted a more formal definition of the term “planet” by the International Astronomical Union (IAU). Their updated description excluded both Pluto and Eris but produced a new, more apt designation of “dwarf planet”.

Pluto is mostly made of rock and ice. It is ~70% of the diameter of the moon and ~one-sixth the mass. In fact, it is about half as wide as the United States.

In the summer of 2015, NASA’s spacecraft New Horizons flew by Pluto and sent pictures back to Earth.

How long did it take New Horizons to reach Pluto?

About nine and a half years

When the solar system was formed, gas, dust, and rocks pulled together to form planets. The planets then swept any remaining debris into the sun or pushed it to the edge of the solar system. Beyond Neptune, at the edge of our solar system, is a region of space filled with icy bodies that slowly revolves around the sun. It is called the Kuiper Belt.

The mission of NASA’s New Horizons spacecraft was to explore Pluto and the Kuiper Belt. New Horizons was launched on January 19, 2006. Its closest flyby to Pluto was July 14, 2015. It took only nine and half years to travel three billion miles. It zipped by Pluto at 30,800 miles per hour.

NASA seeks to understand how Pluto and its moons fit into the rest of the solar system. It is unlike both the inner rocky planets and the outer gaseous planets. It was designated a dwarf planet but it is actually an ice dwarf planet and a resident of the Kuiper Belt.

How many moons does Pluto have?


Pluto has a massive moon, Charon, that is nearly half its size. This moon is so big that Pluto and Charon are sometimes considered a double planet system. Charon doesn’t move around Pluto. Instead, both bodies rotate around a common center of mass that lies outside either body, making for a wobbly orbital dance.

In preparation for the New Horizons flight, the Hubble Telescope captured images from Pluto and discovered more moons: Nix and Hydra in 2005, Kerberos in 2011, and Styx in 2012.

The four smaller moons rotate around the binary system of Pluto-Charon. The dynamically changing gravitational field caused by Pluto and Charon makes Nix, Hydra, Kerberos, and Styx rotate chaotically. These little moons are spherical and each has its own unique spin.

New Horizons was expected to find additional moons when it arrived, but none were seen.

Researchers believe that there is a planet somewhere within the Kuiper Belt and have already given it a nickname. What is it?

Planet Nine

During the excitement surrounding the discovery of Pluto in 1930, there was rush to consider it a planet, the ninth in a series of planets. That designation lasted seventy-six years until 2006 when it was demoted to a dwarf planet.

Astronomers studying the Kuiper Belt found the orbits of the objects there swung out in an odd fashion that would only make sense if there was a gravitational pull from an unseen object. If this object exists, it would be massive โ€“ 10 times the mass of Earth and 5,000 times the mass of Pluto. It would be our true ninth planet, Planet Nine, and it would exist at the far edge of our solar system. It has yet to be discovered.

This week's answer:

What compounds act as a preservative when added to alcoholic drinks?


Sulfur dioxide added directly to alcoholic drinks slows down oxidative reactions. It is added in the form of sulfites (ex: sodium metabisulfite, potassium metabisulfite). When mixed with water, these compounds produce sulfur dioxide.

Sulfur dioxide is an antioxidant and antimicrobial. In wines, it helps to preserve color and flavor, and also to inhibit the growth of yeast, molds, and bacteria.

Sulfites occur naturally in some foods and beverages as a result of fermentation, but can be artificially enhanced to reach the proper effective concentration. In addition to alcoholic drinks, sulfites are added to dried fruits to keep them from browning, and to processed meats to keep them fresh.

Next week's question:

Which contains more sulfites: red wine or white wine?


Past questions and answers are in the trivia archives: 2012 / 2013 / 2014 / 2015 / 2016

Questions? Comments? Corrections? Contact Mary Leonard,