A Christmas Star That Is Not a Star

conjunction
The conjunction that appears as a “star” – Image: NASA

Popularly known as the “Christmas Star,” at this time of 2020 you can observe this “star” that is actually the planetary conjunction of the bright planets Jupiter and Saturn.  The conjunction culminates on the night of December 21, but is visible in the evening sky now.

We know that Galileo Galilei in 1610 discovered the four moons of Jupiter – Io, Europa, Ganymede, and Callisto. He also saw in his telescope a strange oval surrounding Saturn. Later that halo would be seen in better telescopes as Saturn’s rings.

In 1623, our solar system’s two giants, Jupiter and Saturn, moved together until Jupiter caught up to and passed Saturn. This astronomical event is known as a “Great Conjunction.”

The planets regularly appear to pass each other in the solar system. Jupiter and Saturn align in the sky about once every 20 years.

You can imagine ancient skywatchers seeing this conjunction as a bright star at this time of solstice or Christmas as something miraculous.

But this year has several additional celestial wonders. First, it has been almost 400 years since the planets passed this close to each other in the sky. Astronomers tell us that it has been nearly 800 years since the alignment of Saturn and Jupiter occurred at night so that people around the world can see this conjunction.

The 21st is also the Winter Solstice. These two planets will be so close (a tenth of a degree apart)  and will appear on the long solstice night to be one “star.” No telescope needed to observe the conjunction. Actually, the naked eye will blur the two together more than an optical view.

If you believe in coincidences, this is an interesting one. If you don’t believe in coincidences, this is more interesting.

Like many celestial events when viewed from Earth, these giants will appear close together, but they will remain hundreds of millions of miles apart in space.

On this snowy night, I will venture out to an unobstructed view of the sky, an hour after sunset, and look to the southwestern sky. Jupiter will look like a bright star and Saturn will be slightly fainter and will appear slightly above and to the left of Jupiter. At the solstice, Jupiter will overtake it and they will reverse positions in the sky.  If you do have a telescope or good binoculars you might see Jupiter’s four large moons. The Moon will be at its First Quarter tonight with 45% of it illuminated.


You might want to watch the NASA Science Live episode on the conjunction live at 3 p.m. EST today on NASA Television and the agency’s website, along with the NASA FacebookYouTube, and Periscope channels.

the planets
Our solar system –  Image by Comfreak from Pixabay

 

Venus, Saturn, Jupiter and a Crescent Moon

If you were up early this morning you would have seen a lineup in the morning sky of Venus, Saturn and Jupiter on a line with the morning crescent moon. The lineup will be around for the next few mornings, so if there is a clear sky and you are up more than an hour before sunrise, it will be easy to spot.

Look east to the sunrise and the Moon will slide its way up past the three planets.

planets
The planetary lineup – via earthsky.org

This morning the waning crescent moon was right next to Jupiter. (This is best viewed from North America.)

Saturn and Venus are east of Jupiter and the line they seem to all be on is the ecliptic, or Earth-sun plane. This is the plane on which the other planets in our solar system and the moon all orbit, so we view them as being on this line.

Falling Stars from the Chariot of the Sun

meteors
Geminids in the northern hemisphere by Asim Patel – Own work, CC BY-SA 3.0, via commons.wikimedia.org

The Geminid meteor shower is a very reliable annual meteor shower that will visit us again this week.

The next several nights are probably the best nights for watching with the peak morning is likely to be December 14, 2018, but the morning of December 13 might offer a good display, too, and meteor watchers have been catching Geminids for some nights now.

You can watch in the late evening, but the best viewing hours are typically around 2 a.m., no matter where you are on Earth. And this year there will only be a waxing crescent moon, so moonlight won’t wash out the darkness.

The meteors appear to come from (radiate from) the constellation Gemini, which rises around sunset and moves overhead into morning. The best views are usually between midnight and 4am.

The Geminids are slow-moving dust particles when they hit the Earth’s atmosphere. “Slow” is relative here – they are only moving at 22 miles per second. The friction with air molecules will burn them up and make a nice glow for us to watch.

These showers are caused by the object 3200 Phaethon, which is an asteroid. That is unusual and this is one of the only major meteor showers not originating from a comet. This asteroid has an orbit that brings it closer to the Sun than any other named asteroid. And that is how the asteroid got its name.

Phaeton
Gustave Moreau: Fall of Phaéton (Chute de Phaéton) watercolor study, via Wikimedia

Phaethon is a name from mythology.  Phaethon was the Ancient Greek name for the planet Jupiter, a planet whose motions and cycles were observed by the ancients and often used in poetry and myth.

In mythology, Phaethon’s father was the sun god Helios who granted his son’s wish to drive the sun chariot for a day.  Phaethon was unable to control the horses and to prevent the chariot from hitting and destroying Earth, Zeus knocked it out of the sky with a thunderbolt. Phaethon fell to earth and was killed.

Of course, meteors are not falling stars, and they are not coming from the chariot of the Sun, but it does make for a good story.

 

That’s No Star

Tonight, July 20, that bright “star” near the moon is no star. It is Jupiter.

Jupiter is shining more brightly than any star now (though Mars is even brighter). The moon and Jupiter are particularly close tonight and during this weekend.

Venus and Mars are the other starlike objects that outshine Jupiter in the evening sky, but you can tell the difference. Venus is in the western sky as darkness falls. Mars is in the southeast horizon at nightfall.  Jupiter will be near the moon for this weekend.

The Moon, Jupiter and Spica

This past Memorial Day Weekend, we had some clear skies and some rainy ones. On one clear evening in Paradelle I was able to see a very bright “star” near the moon. It looks like a star, but it is Jupiter.

Venus sets in the west not too long after the sun sets, and the Moon and Jupiter were the two brightest objects in the sky.

I knew to look for a fainter true star. It is fainter but still one of the brightest stars, even in the moon’s glare. This is Spica. It is the brightest star in the constellation Virgo the Maiden. I’m not very knowledgeable about the zodiac, but I know it is a key star in that study.

Spica is a first-magnitude star, but it appears much fainter than Jupiter. That is because Jupiter is relatively close (or at least nearer)to Earth. This is what draws me to gazing at the night sky is my semi-knowledgeable way: the idea that Spica is about 262 light-years away, and I am looking at its light.

The universe makes me think about the original meanings of words like WONDERful and AWEsome.

Spica is the easiest star to spot in Virgo. There is a saying to find Spica you can “follow the arc of the Big Dipper to Arcturus and speed on to Spica.” But that probably doesn’t make it any easier for the average Earthling to find because most people know very little about the night sky.

Besides Spica, other bright stars in Virgo include many I had never heard of: β Virginis (Zavijava), γ Virginis (Porrima), δ Virginis (Auva) and ε Virginis (Vindemiatrix). Other fainter stars that were also given names are ζ Virginis (Heze), η Virginis (Zaniah), ι Virginis (Syrma) and μ Virginis (Rijl al Awwa).

Again, the wonder and awe of all this is discovering that one of the stars, 70 Virginis, has one of the first known extrasolar planetary systems and it contains a confirmed planet 7.5 times the mass of Jupiter. I can’t even really grasp the size of my own Earth. And the star Chi Virginis has one of the most massive planets ever detected, at a mass of 11.1 times that of Jupiter. And there are 35 verified exoplanets orbiting 29 stars in Virgo.

All this makes me feel like such a small part of the universe. But i also makes me feel part of the universe.

 

This first appeared on One-Page Schoolhouse

Trump Says Sun Equally to Blame for Blocking the Moon

There’s all kinds of fake news these days. There is even fake news about fake news. There has pretty much always been fake news about science, even before we used the word science.

Imagine all those ancient people wondering about lunar and solar eclipses. How many of them did eye damage by staring up at a solar eclipse? Were the gods or a God punishing us by taking away the Sun, and further punishing those who dared to look at it? Did they pray the Sun would return and rejoice when it did return?

In July 2015, an article online claimed that NASA had confirmed that the Earth will experience 15 days of total darkness between November 15 and November 29, 2015. Supposedly, this had not occurred in over one million years.

Of course, it was fake news. The original story seems to have come from a fake news website Newswatch33 (no link to it here which would only increase its search ranking).

The story is evergreen and came back as happening in November 2016 as that date approached the following year, and I saw it this week as a link in some Facebook feeds as an event for November 2017. I suspect the eclipse publicity brought this “November Blackout” story back and social media will give it some life again. Any number of legitimate news, science or debunking websites will tell you it’s completely fake.

And yet some people believe it. Wouldn’t you think that if  NASA knew that the world will remain in complete darkness for 15 day it would have been covered by the real media and not just by your friends on social media?

The “explanation” of this supposed event was that it would occur because of  another astronomical event between Venus and Jupiter. It was explained that during the conjunction between Venus and Jupiter on October 26, light from Venus would cause gases in Jupiter to heat up and those gasses will cause a large amount of hydrogen to be released into space. The gases will reach the Sun and trigger a massive explosion on the surface of the star, heating it to 9,000 degrees Kelvin. The heat of the explosion would then cause the Sun to emit a blue color. The dull blue color will last for 15 days during which the Earth will be thrown into darkness.”

This bullshit jumps off from the term “conjunctions,” which are real but mostly just visual phenomena. Conjunction, in astronomy, is an apparent close meeting or passing of two or more celestial bodies. It is hardly a rare thing. The Moon is in conjunction with the Sun every month at the phase of New Moon, when it moves between the Earth and Sun and the side turned toward the Earth is dark. That two things in the sky look closer together from our point of view on Earth does not mean that they are in fact close together.

Are Jupiter and Venus ever in conjunction? Yes, and when that happens they can still be over 800 million km apart. (For perspective, the Sun and the Earth are about 150 million km apart.)

Jupiter doesn’t affect the Sun. At about 778 million km from the Sun,  Jupiter could swap places with Venus or Jupiter could disappear and the Sun would go on shining normally.

I suppose we Earthlings would like to believe that amazing things can happen. Add to that the pretty poor understanding of basic science (especially of things astronomical) that most people have retained (oh, it was taught to you in school), and these ridiculous stories more easily gain traction. It’s not that fake news didn’t make its way around a town, country or the world a thousand years ago. Surely, it did – but slowly. Since the rise in popularity of the Internet and social media sharing, hoaxes and fake news has proliferated at an incredibly fast rate.

One of the other big fake science stories is the  “Mars Hoax” which pops up every August online since 2003. That year, a historically close approach of the Red Planet to Earth actually did occur. But it has become an annual event online and the closeness has grown so that the headline or link will say that on some particular night in August, Mars will appear as big as the full moon. Totally untrue. That didn’t even happen in 2003. It will never happen.

This year there was a new fake story to start the year saying that on January 4, 2017 it would be “Zero Gravity Day”  when people on Earth would be able to experience weightlessness if they jumped into the air at a specific moment that day. How many people believed that one? I don’t have that number, but I suspect it is not zero.

That particular story sent me back to childhood and listening to the humorist Jean Shepherd on the radio. At least once, he tried to get listeners to jump as high as they could on his command to test a theory that if we removed enough weight from the Earth all at once, we could tip the planet. We knew it was Shep yanking our chain, but I did jump on his command just for the heck of it.

I was talking to a friend a few weeks ago about fake news and I said that, of course, everyone knows that headlines from The Onion or The Borowitz Report are quite deliberately fake and satiric. My friend didn’t know that and didn’t think he had ever seen any of those stories. As someone on Facebook and Twitter, I’m sure he has seen them. I hope he didn’t believe any of them.

Sure, Andy Borowitz is published by The New Yorker, a very legitimate and respected magazine, but his Borowitz Report web page says right at the top “Satire from the Borowitz Report. Not the news.” But you don’t see that tagline disclaimer when someone posts a link to one of his stories. You see “Trump Says Sun Equally to Blame for Blocking the Moon,” and think that since President Trump has said so many ridiculous things lately that it might actually be true. It is getting harder to be ridiculous these days.

The Onion‘s headlines tend to be a bit easier to spot as satire – “‘My Work Here Is Done,’ Smiles Contented Bannon Before Bursting Into Millions Of Spores,” for example – but I’m sure there are people who read them (and pass them on) sometimes as real news.  SAD – as our President might comment about this in a tweet.