Showing posts with label Jupiter. Show all posts
Showing posts with label Jupiter. Show all posts

January 13 - Galileo Discovers Callisto

    Posted on January 13, 2022


This is an update of my post published on January 13, 2011:






News flash: January 13, 1610: 

Galileo Galilei discovered a fourth moon of Jupiter. 

But he did not choose the name “Callisto”!


To some extent people who discover new lands, comets, animals, elements, moons (and so on!) get the privilege of naming them—but at times those names are changed later. Galileo called this moon IV, the Roman numeral “4,” to distinguish it from Jupiter's other moons, I, II, and III. This turned out to be confusing, as many other planets turned out to have their own moons—quite a lot of moons, in some cases!—and we now know that Jupiter alone has 79 moons (at least! —stay tuned!).


The "Galilean moons" are Jupiter's largest four, the four Jovian
moons discovered by Galileo. 

The photo below shows roughly what Galileo would have seen
through his telescope.



A German astronomer who lived at the same time as Galileo, Simon Marius, claimed to have discovered Jupiter's moons before Galileo. Looking at the evidence, it seems possible that Marius discovered the Jovian moons independently of Galileo—but a few days later. Marius suggested naming Jupiter's moons for female mythological characters associated with Jupiter: Io, Europa, Ganymede, and Callisto. But because of the dispute over priority, Galileo never adopted those names—he stuck with his Roman numerals.




It seems that Marius's suggested names were officially adopted in the mid-1800s and became commonly used in the 1900s. At that point, Roman numerals were used for the smaller, newly-discovered V through XII, but in the 1970s the smaller Jovian moons were named after other lovers, favorites, and daughters of Jupiter. A few of the smaller moons are still waiting for a name, as far as I can tell.

Take a Peek at Jupiter's Moons

With a small telescope or a good pair of binoculars, you can spot Callisto and Jupiter's other largest moons. Check for the time when Jupiter will rise in an almanac such as the Time And Date online almanac.  

Here's a great video about why Callisto might be home to a human colony some day!




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May 17 - Jupiter's Belts Discovered!

 Posted on May 17, 2021

This is an update of my post published on May 17, 2010:



You've seen pictures of Jupiter, right? Those reddish-brownish stripes, the Great Red Spot, all those swirling clouds?



Of course, there was a time, before telescopes, when Jupiter was just a bright “star” in the sky and none of these details were known.

On this day in 1630, Jupiter's belts were first discovered by Jesuit astronomer Nicolas Zucchi.

(Notice that the light-colored stripes are usually called "zones" and the darker-colored stripes “belts”; the Great Red Spot, which is associated with the Southern Equatorial Belt, is sometimes called the belt buckle.)

In 2010, an amateur astronomer discovered that Jupiter's Southern Equatorial Belt had disappeared.


















You see, earlier that year Jupiter went “behind” the Sun, from Earth's point of view, and we weren't able to observe it for a few months. When it emerged from the Sun's glare, the belt was gone.

Yes, that's right--Jupiter had a belt buckle with no belt!

Don't worry, though. The belt has since reappeared, and apparently the belt has disappeared and reappeared several times. Scientists guess that, when Jupiter's temperatures drop a bit because the planet is moving farther away from the Sun (because planets circle the Sun in slightly oval orbits rather than perfectly round ones), the cooling temperatures cause the dark chemical clouds that make up the belt to sink lower into the atmosphere. When the belt sinks, light clouds close in above it and hide it from our view. Of course, eventually Jupiter gets a bit closer to the Sun again, warms up, and voila! Its belt reappears!


Quick Quiz on Jupiter

1. Who was Jupiter named after?
A. the Greek god of war
B. the king of Greek gods
C. the Roman god of war
D. the king of Roman gods
2. How many moons or satellites does Jupiter have?
A. 2
B. 16
C. at least 63
3. Does Jupiter have rings?
A. Yes
B. No
C. Sometimes
4. Jupiter's Great Red Spot is most like a ____.
A. satellite
B. dust storm
C. hurricane
5. How large is the Great Red Spot?
A. the size of Earth's moon
B. the size of the Earth
C. more than twice the size of the Earth
6. Counting out from the Sun, Jupiter is the ____ planet.
A. third
B. fourth
C. fifth
D. sixth
7. In size, Jupiter is the ____ planet.
A. largest
B. second largest
C. smallest
8. Jupiter is considered one of the ____.
A. inner planets
B. gas giants
C. rocky planets
9. The first person to spot Jupiter's moons was ____.
A. Galileo
B. Sir Isaac Newton
C. Copernicus
10.The adjective form of Jupiter's name is ____.
A. Jupiterian
B. Jovian
C. Jupiterial

 



ANSWERS: 1.D – 2.C – 3.A – 4.C – 5.C – 6.C – 7.A – 8.B – 9.A – 10.B


Play Around in the Solar System
Do you know how much you weigh? On Earth, that is! Find out how much you would weigh on Jupiter and the other planets.

 

Did you know that, if Jupiter were the size of a basketball, the Earth would be a bit smaller than a pingpong ball?! Learn about the relative sizes and distances of the planets in the solar system by using this conversion tool. (If you want, you could make a scale model!)

 


How old would you be on Jupiter? This gigantic planet is so far from the Sun (compared to the Earth), that one Earth year is just a fraction of a Jovian year. Find out your age here.

 


Can you imagine living on one of Jupiter's moons? Your nighttime sky might look something like this:

 
Europa is one of Jupiter's most interesting moons, with the possibility of an ocean under the surface ice, and even life. A long time ago, in1903, an artist painted this picture of Europa as a much warmer, full-of-life moon...

View of Europa from the Book "Астрономия для дам" (1903) K.Flammarion
...but nowadays we think Europa would look more like this.







"Courtesy Jet Propulsion Laboratory. Copyright (c) California Institute of Technology, Pasadena, CA. All rights reserved."






 

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January 22 - Space-Stuff Day

 Posted on January 22, 2021

This is an update of my January 22, 2010, post:



On this date in 1992, Dr. Roberta Bondar, Canada's first female astronaut, became the first neurologist to enter space. She flew on the Discovery space shuttle and did microgravity experiments with a variety of organisms. Dr. Bondar also served as NASA's head of space medicine.


On this date in 1997, American Lottie Williams became the first—and, so far, only— human ever reported to be hit by human-made space debris (also known as “space junk”). Williams was jogging in a park near her Oklahoma home very early in the morning, and she saw a brilliant fireball-type meteor. She felt a “gentle tap” on her shoulder and looked down; on the ground was a piece of blackened metal. 

Later it was confirmed that the metal was a piece (shown in her hands, above) of a fuel tank for a rocket that had launched a U.S. Air Force satellite the year before. The rest of the fuel tank crashed into a field in Texas (shown below).



On this date in 2003, we said goodbye to Pioneer 10, the first thing made by humans to leave the solar system. The next day (January 23, 2003) scientists were able to detect the last feeble signal from the spacecraft as it continued to speed away from Earth.


Launched in 1972, Pioneer 10 was the first spacecraft to fly through the asteroid belt and to fly by Jupiter. Even though it accomplished these two main goals before two years had passed, Pioneer kept up the studies and transmissions as it streaked through the outer regions of our solar system. All told the spacecraft studied interplanetary and planetary magnetic fields; solar wind parameters; cosmic rays; the heliosphere; neutral hydrogen abundance; distribution, size, mass, flux, and velocity of dust particles, Jovian aurorae and radio waves, atmosphere of Jupiter and some of its satellites. Of course, it also photographed Jupiter and its satellites.


The mission was formally ended in 1997. After that time the probe was used in training flight controllers on how to acquire radio signals from space. Scientists believe that no longer have contact with Pioneer 10 because it is too far away and because the power supply is dwindling—not because of equipment failure.

A Message to Aliens?

Before Pioneer 10 and its sister spacecraft Pioneer 11 were launched, a journalist named Eric Burgess had a great idea—putting a message of some sort to any alien intelligences that may discover the probe, somewhere, someday. He made his suggestion to Carl Sagan, a famous astronomer and science writer.

Sagan loved the idea and, with the help fellow scientist Frank Drake and wife Linda Salzman Sagan, created a clever message to unknown creatures and minds, trying to communicate with images a little about who we humans are and where we live.


The plaque is 9 inches by 6 inches and made of gold-adonised aluminum. Here is an explanation of what the various symbols mean. And here is a great website to learn more about Pioneer 10.

Read about Space Junk.

Build a Pioneer 10 paper model.

Run gravity simulations.



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