Missed Conjunction

The evening of August 27, 2016, was scheduled to feature the conjunction of the planets Venus and Jupiter shortly after sunset, a marvellous mere ½ degree apart, the same as the apparent diameter of the Moon, which is pretty darn close in a big, big sky. That’s a must-see in my book! As a last minute decision I went for the best nearby vantage point I could think of, which was the west side of Slottsfjellet (“Castle Mountain”) in Tønsberg, a mere 20 minute drive from home. I was gonna shoot me some planets!


Hiding behind them there cloudses

Although the sky was mostly clear and outstandingly beautiful with the sunset and all, I missed the conjunction on account of lovely but otherwise annoying clouds on the horizon. On the upside, on account of wearing shorts, I have several brand new mosquito bites to keep me entertained the next few days.


Screenshot from Star Walk overlayed on camera view

I followed the planets until they were well below the horizon. Not only were they hiding behind clouds the whole time, the sky was still bright enough that they probably wouldn’t have been very visible anyway.

According to Space.com, “the next time Venus and Jupiter will get this close will be in November 2065,” by when I will be a whopping 96 years young. Bring it on!

In the mean time I’ll just leave you with this.


Screenshot from Star Walk overlayed on camera view

The sky beneath my feet.
Stars.
Space.
Darkness and light.
Emptiness.
And grass.

~

Mars The Size Of The Moon — Impossible, But What If?

Did you get the message too, that on August 27 the planet Mars would pass so close to the Earth that it’d look as big as the full Moon in the sky? If you did, don’t believe a word of it, because that will never happen. That message is an echo of a hoax that has been going around the Interwebs every year since 2003 when, in fact, on August 27, Mars was closer to Earth than it had been since some 60 000 years ago, when the Neanderthals were still a going concern. So how big did it look? Not very, and I know this because I looked at it very, very hard indeed. It was a pinhole of light. A slightly red, bright star.

It’s a pity, though, because the sight of it as big as is rumoured would quite simply be absolutely mindbogglingly spectacular! I for one would gladly sign up to watch that.


Alas, not even remotely likely to happen.

The body of Mars is just under twice as wide (1.95 times) as that of the Moon, and in order to look the same size it would therefore have to be just under twice as far away. That would take it to 749 580 km. But Mars’ orbit can never take it that close to the Earth; the closest it got in 2003 was about 55 750 000 km, which is still 145 times as far as the Moon’s orbit.

Some even claim that this extreme close approach is the only time you can see Mars without a telescope, which is also wrong. If you’re in an area without too much light pollution, you can easily see Mars in the sky for much of the year, using nothing but your unaided eyes. It’s a tiny, bright dot in the sky, but it’s definitely visible. For instance, I took this photo of it with my iPhone on December 15th (blogged separately here), and for the record it looked much clearer to the eye than to the camera.


If an iPhone can see this, you can see this.

But how big can the planets actually get in the sky? There’s the chance you’ve seen science or science-fiction illustrations where the artist has taken some liberty with realism, giving the impression that giant planets in the sky would be a likely everyday occurrence, which is misleading to say the least. For measure, I put together this little graphic to illustrate the matter, not just for Mars, but for all the planets in our solar system.


Click the image to see full size (1080px square) with moon 1000px tall.

In order to show the planets at all, I had to significantly up the scale. In reality, if you look at the full Moon in the sky, next to your outstretched arm, then the Moon should appear as small as or even a little bit smaller than the nail on your thumb. So if you imagine the Moon in this picture that much smaller, then that’s how much smaller those planets are going to look, too. They are sorted by maximum apparent size, and their relative sizes should be fairly accurate. You will notice that both Venus and Jupiter show up as looking far bigger than Mars. Venus is both bigger and closer to the Earth than Mars is, whereas Jupiter is much, much farther away, but also considerably larger.

Just because someone asked, which tells me that I wasn’t sufficiently clear about it, if this was all entirely to scale, i.e. the Moon at its actual visual size, the entire picture would be as tiny as this one (right), and hardly any of the planets would show up at all. Remember, the Moon is the size of your thumbnail, and the planets should be scaled down accordingly. Ok?

Also keep in mind that the graphic shows only the planets’ relative sizes, and not their actual brightness or detail. For instance, both Venus and Mercury, whose orbits are between the Earth and the Sun, will be invisible when they are at their closest because we’ll be looking at their night side, which is inconveniently dark. The only times we’ll be able to see them at their closest at all is when they happen to be crossing in front the face of the Sun, which for Mercury occurs 13-14 times every century, and for Venus twice every 130 years (which most recently happened in 2004 and 2012, blogged separately here). All the other orbits are well outside that of ours, so we will always be seeing those planets’ daylight side.

For reference, here are the numbers:

Name

Radius

×Moon

Closest Distance

×Moon

Scale
Moon*

1 737 km

 

384 400 km

 

1.000
Venus

6 052 km

3.484

38 000 000 km

99

0.0352
Jupiter

74 492 km

41.2

588 000 000 km

1 530

0.0269
Mars

3 390 km

1.95

55 758 000 km

145

0.0134
Saturn

54 364 km

31.3

1 200 000 000 km

3 122

0.0100
Mercury

2 440 km

1.4

77 000 000 km

200

0.00700
Uranus

25 559 km

14.7

2 600 000 000 km

6 764

0.00217
Neptune

24 764 km

14.3

4 300 000 000 km

11 186

0.00128
Pluto**

1 187 km

0.683

4 737 000 000 km

12 323

0.0000554

* The distance listed for the Moon is the average, not the closest. The Moon’s orbit varies between nearest at 356 400 km and farthest at 406 700 km.

** Pluto is included in this overview for demonstrative purposes only, for two reasons: First, it’s no longer counted as one of the main planets, which has been a matter of considerable boo-hoo since 2006, and second, it’s far too tiny and too far away to even show up unless I make the entire picture ridiculously huge. Neptune is both closer and much bigger than Pluto, and it still only shows up as a single, barely visible pixel in the large version of the image where the Moon is 1000 pixels tall. If I had attempted to draw Pluto at that scale, it would have been 0.00000134 pixels wide. In order to make Pluto a single pixel wide, the full image would have to be enlarged by a factor of twenty. Ain’t nobody got time for that! Incidentally, Pluto’s closest approach to Earth for another 200 years was on July 3, 2014, at 4 737 000 000 km, but its current distance is 5 085 500 000 km.

The relations between the planets’ actual sizes, their distances and their apparent sizes, is a tough noodle to flex your mind around, as demonstrated in the following video, where a group of practical-minded enthusiasts attempt to put those factors into proper perspective. It turns out you need quite a lot of room for that.

To Scale: The Solar System

“Every picture of the Solar System that we ever encounter is not to scale. If you put the orbits to scale on a piece of paper, the planets become microscopic, and you won’t be able to see them. There is literally not an image that adequately shows you what it actually looks like from out there. The only way to see a scale model of the Solar System is to build one.”

But lets say, just for the fun of it, that the planets could come near enough to compete with the Moon for sky dominance. How close or far away would they have to be? I gathered them all in this overview, sorted in no particular order, and although the Earth is naturally absent, since we’re standing on it, I’ve included Pluto here as well, just because Pluto needs a little love too.


Click the image to see full size (1000px square).

The above is how they’d look head-on, which is nice and lovely and all that. How, then, and I ask the question so that you won’t have to, would they look from the side? Well, if you’re in the mood for a long, long scroll, you can click on the image below.


Click the image to see full size (500px × 4250px).

Again, just to keep the Ninth Planet fans happy, I’ve included Pluto. It’s interesting to note that, in this illustration, it is posing even closer to Earth than the Moon is, but that is simply because it is smaller than the Moon. Remember, this one is not about actual distances, but about placing every planet at such a distance from the Earth that it appears the same size as the Moon. Hence the smaller ones will have to be closer, and the bigger ones have to be far, far, farther away. So far that Jupiter, the biggest, ends up floating more than a tenth of an Astronomical Unit away (a nine and a halfth of an AU, to be precise), with an Astronomical Unit being the average distance between the Earth and the Sun, or roughly 150 000 000 kilometres. That’s quite a distance, but then again Jupiter is a big fellow.

Curiously enough, as the planets in this line-up appear the same size as the Moon, they also appear the same size as the Sun. This is linked to the fact that although the Sun is 400 times bigger than the Moon, it is also 400 times farther away from the Earth as the Moon is, which is why we have those spectacular solar eclipses which have frightened the wits out of people all the way back to ancient times, and even today.

Mind you, as awesome as this would have looked, we would have been in serious trouble, and the reason for that is gravity. Short term wise, the gravity of the Moon is what causes the tides in our oceans. With the added gravity of any one of the planets would increase tides by a considerable factor, causing tsunamis, world-wide flooding, death and destruction. Long term wise, the gravitational balance between the Earth and the Sun is what keeps Earth in its orbit. That balance is delicate, and such a close approach by any one of the planets would greatly disturb it, permanently changing our orbit, which in turn would drastically affect the climate to become far colder or far hotter, possibly to the point where we’d find ourselves irreversibly extinct, along with most or all other life forms with whom we share the world.

How far can we take this? Quite a bit, it turns out. Youtube user Yeti Dynamics has made a few videos that push the envelope pretty far, being as spectacular — and frightening, to be honest — as they are unlikely.

If the Moon were replaced with some of our planets

We started with the premise that Mars might look as large as the Moon. What if some of the planets were actually orbiting the Earth in place of the Moon? Aside from the side effect from the massive increase in tidal forces, it would look awesome.

If the Moon were at the same distance as the ISS

The Moon isn’t the only thing out there orbiting the Earth. We have all sorts of satellites for all kinds of purposes at all kinds of distances, as well as an entire space station with people on it! The ISS is just 400 km out, which, to be honest, isn’t all that far into “deep space”, but it does give a tremendous close-up orbital view of our planet. Apollo astronauts on the Moon had an equally spectacular view of home, but it was much smaller in their sky. What say you, we bring the Moon closer to let the Apollo crews have a view matching that from the ISS?

A visit from Saturn: What if Saturn flew past the Earth

What if someone stepped on Saturn’s emergency brakes, making it slow down or even stop? All planets require constant speed to keep them in orbit, so a slow-down could lead to only one thing: The planet would fall inwards, towards the Sun. Imagine ourselves in the path of the ringed planet’s perilous plunge, or try the video which has this already imagined.

How did I do this? First of all, I’m not a genius. It’s easy to find the numbers on planets’ sizes and orbits, which are all available on easily accessible websites like Wikipedia, as well as minimum distances, which takes a modicum of Googling. Once the numbers are on hand, it’s all just basic arithmetic (simple addition, subtraction, multiplication and division) with a touch of geometry, both of which should be familiar to anyone who has completed nine to ten years of public school, and you’re allowed to use a calculator. It’s not rocket science, people! What I did do to take it that one step further was to include all the planets, not just Mars. The illustrations are just a matter of putting the numbers to pixels.

What prompted me to make this blog post and planet size overview was the surprising discovery that a number of people that I know, whom I hasten to add are quite intelligent and otherwise well educated, had absolutely no idea how planetary orbits work, or how far from each other the planets are, and gladly accepted the suggestion that Mars, or even Neptune, might occasionally give Earth a close fly-by. It worries me that people in general are so, I’m sorry to say, willing to accept wild nonsense as fact, and I hope that with this, I’ve managed to both educate and amuse.

Thanks for reading 🙂

Relevant links

Pluto: Radius 1 187 km, current distance 5 085 500 000 km (closest 4 280 000 000 km)

Moon radius = 1 737.1 km (0.273 Earths); average distance = 384,400 km
Mars radius = 3 389.5 km (1.95 × moon); closest distance: 55,758,006 km (145 × moon)
Jupiter radius = 74,492 km equatorial (41.2 × moon); closest distance = 588,000,000 (1,530 × moon)
Venus radius = 6,051.8 km (3.48 × moon); closest distance = 38,000,000 (98.9 × moon)
Saturn radius = 54,364 km polar (31.3 × moon); closest distance = 1,200,000,000 km (3,122 × moon)
Mercury radius = 2,439.7 km (1.4 × moon); closest distance = 77,000,000 km (200 × moon)
Uranus radius = 25,559 km equatorial (14.7 × moon) ; closest distance = 2,600,000,000 km (6,764 × moon)
Neptune radius = 24,764 km equatorial (14.3 × moon); closest distance = 4,300,000,000 km (11,186 × moon)

APPARENT SCALE
Moon width = 1
Planet width = dWidth / dDistance
Mars width = 1.95 / 145 = 0.0134
Jupiter width = 41.2 / 1530 = 0.0269
Venus width = 3.48 / 98.9 = 0.0352
Saturn height = 31.3 / 3,122 = 0.0100
Mercury width = 1.4 / 200 = 0.00700
Uranus width = 14.7 / 6,764 = 0.00217
Neptune width = 14.3 / 11,186 = 0.00128

http://mars.nasa.gov/allaboutmars/nightsky/mars-close-approach/archive/#2003
«But not since the Neanderthals lived have Earth and Mars been quite as close as on August 27, 2003 at 9:51 Universal Time (the time in Greenwich, England) — 55,758,006 km (34,646,418 miles) from center to center. That was the nearest the two planets have been in almost 60,000 years!»

http://mars.nasa.gov/allaboutmars/nightsky/mars-close-approach/



Venus
at 1 339 250 km (3.48x)
closest 38 000 000 km (99x)

Mercury
at 538 160 km (1.4x)
closest 77 000 000 km (200x)

Mars
at 749 580 km (1.95x)
closest 55 758 000 km (145x)

Jupiter
at 15 837 280 km (41.2x)
closest 588 000 000 km (1 530x)

Moon
at 384 400 km

Neptune
at 5 496 920 km (14.3x)
closest 4 300 000 000 km (11 186x)

Uranus
at 5 650 680 km (14.7x)
closest 2 600 000 000 km (6 764x)

Saturn
at 12 031 720 km (31.3x)
closest 1 200 000 000 km (3 122x)

Pluto
at 262 545 km (0.683x)
closest 4 737 000 000 km (12 323x)

http://www.businessinsider.com.au/saturn-look-like-closer-than-the-moon-2014-5

Planets Hugging Virgo

The celestial trio of Venus, Mars and Jupiter are spreading wider apart, but they are still slightly dominating their part of the south to south-eastern sky in the last hour before sunrise. Right now they’re pretty much hugging the constellation Virgo. Here is what my daughters and I spotted on our way to our respective buses to school and work in the early morning hours of December 15th, with a cool and clear sky above us.

Photos © Bjørnar Andre Haveland
Click images to see larger versions.

VMJ spanning Virgo

The original iPhone 5s shot, at 07:48 (my attempt to use the Nikon was thwarted by the bus arriving right on time for a change). On most screens this will show up as far too dark to see much more than the bright specks of Venus (left) and Jupiter (right). With a bit of luck, optimal illumination, fabulously good eyesight and an impressively clean monitor, you’ll just possibly spot Mars as a barely distinguishable pixel somewhere in the middle.

VMJ spanning Virgo

With the exposure adjusted in the extreme, however, Mars and a neighbouring star both show up reasonably clearly, Mars being the upper right of the two, almost precisely smack bam in the middle between Venus and Jupiter.

VMJ spanning Virgo

Labels, for clarity, because mostentimes a bright dot in the sky looks just like any other bright dot in the sky, of which there are a good many. The one labelled Spica is the brightest star in the constellation Virgo, and as far as I can tell from diagrams, lacking a degree in stellar anatomy, it seems to constitute the left hip joint of the virgin in question, assuming she is facing us, otherwise it has to be the right hip joint and we’re looking at her bum. Shame on us!

VMJ spans Virgo

Screenshot from astronomy app Star Walk, showing the same section of the sky, with the planets and surrounding stars in their respective locations, for reference. Incidentally, the bright white orb to Mars’ immediate left is the asteroid 1998 KY26, about 15 metres across, which passed within 800,000 km from Earth on June 8, 1998, but is now about 1.51 AU away, almost as far as Mars, at 1.84 AU. And no, I’m afraid you won’t be able to spot it with the naked eye (in comparison, the Chelyabinsk meteor in 2013 was estimated to be about 20m across).

Untitled

Within the next couple of weeks Venus will drift even further away from the others, so that around December 30th, Mars will be precisely dead center. At that time, the waning Moon will also come swooshing through the trio, possibly making for some nice conjunctions as its crescent grows thinner. On January 6th, the Moon, with just a sliver of a crescent left, catches up with Venus and Saturn, so if you can actually see Saturn, it’ll likely be a lovely little group.

VMJ spans Virgo - meteor composite

We also saw not one but two shooting stars in that precise part of the sky, a few minutes apart, probably leftovers from the Geminids shower during the night. Now, I hasten to point out that this is a composite of the above original, and a meteor trail taken from another picture. Seeing as meteors wait for no man, and to first spot and then photograph one in the same take requires more time than any meteor is willing to hang around for, I had to resort to low-level Photoshop cheating in order to illustrate the event. My apologies.

Planetary Diagonal


2015 © Bjørnar Andre Haveland. Click for larger image.

Eastern sky at 05:51 today (above). Had a lovely view of the crescent moon, with several planets all lined up as if begging to be taken pictures of. Now, in a hurry, as always, to get to the bus to work on time, I couldn’t spare the moments I would have needed in order to fish out the Nikon and play with settings, so this iPhone shot was the best I could do under the circumstances. Terribly annoying, to be honest. Of course the iPhone can in no way do the actual sight any justice at all.

This near 45° line-up consists of (from bottom left) the moon, Venus (brightest), Mars (that barely visible wee li’l smudge of light above and left of Venus) and Jupiter at the upper right.

The thin, crescent moon was precisely the right brightness for this group picture. It’s a shame my equipment wasn’t up to it. I can always try again tomorrow, and make sure I bring both the time and the tools required for the job, but the moon moves quite a distance in the sky from day to day, counter-clockwise*, so tomorrow at this time it will still be well below the horizon. I’m sure that yesterday and the day before that, it was even better, but I wasn’t there to see it. Timing, alas, is everything.

* Clockwise would have been so much better, in which case I would simply have quietly decided to wait and instead bring you the splendidest pictures I that could muster tomorrow.


2015 © Bjørnar Andre Haveland. Click for larger image.

Here (above) I’ve boosted the exposure and contrast somewhat to make Mars a little more visible next to Venus. It’s still barely more than a bright pixel, almost lost in noise, but at least a bit more noticeable than the faint smudge in the first picture.


2015 © Bjørnar Andre Haveland. Click for larger image.

Off the bus, an hour and a half later, give or take, even though I had sufficient time before starting work to take more pictures, the sky had grown far too bright for it. Mars was not at all visible, and Venus and Jupiter just barely so, even the moon was struggling to make itself known against the morning light. They’re still there, though, except for Mars. Can you find them?

Still, weather permitting, I’ve half a mind to bring the tripod for the Nikon tomorrow, along with a few minutes extra time, and at least capture the planets, if not the moon.

Thanks For Boldly Going

Tweet

Congratulations, and great thanks,
to NASA for boldly going and
expanding our horizons!

If you took a baby grand piano, scrunched it up a bit, shook out all the noisy stuff, filled it with cameras, radio transmitters and all sorts of electronics, and then hurled it three billion miles into space, aimed at a tiny, distant, barely visible speck of light that is not even a planet anymore, then you'd be wasting your time, because it looks very much as if NASA has already done it.

~

“If you took a baby grand piano, scrunched it up a bit, shook out all the noisy stuff, filled it with cameras, radio transmitters and all sorts of electronics, and then hurled it three billion miles into space, aimed at a tiny, distant, barely visible speck of light that is not even a planet anymore, then you’d be wasting your time, because it looks very much as if NASA has already done it.”

Oh, and before anyone “catches” me: noble and observant readers of Douglas Adams’ “Last Chance to See” may notice a certain similarity to his memorable description of New Zealand, which is intentional 😉

“If you took the whole of Norway, scrunched it up a bit, shook out all the moose and reindeer, hurled it ten thousand miles around the world and filled it with birds then you’d be wasting your time, because it looks very much as if someone has already done it.”

— Douglas Adams, “Last Chance to See”

%d bloggers like this: