In case you haven't heard of it, Nibiru is a totally nuts idea. Yet it gets many people very scared. I started to get messages about it as a result of writing articles about asteroid impacts, and how we can detect and deflect asteroids. It is possible to have beliefs that don't make any sense if you look at them closely. For instance, if you believe that you can have a square with every point on its edges equally distant from its center in ordinary geometry - that's impossible. That's a square circle. Nibiru is a belief of this sort.
There's yet another Nibiru scare underway. Every few months they "predict" that it is about to hit Earth or cause a cataclysm. I write these articles to help reassure those who are scared. It's for the same reason that David Morrison started publishing his answers to email questions about Nibiru on the NASA website.
Brian Cox colourfully called Nibiru "the imaginary bullshit planet" ("bullshit" is a mild word in the UK often used on TV). Neil deGrasse Tyson called it "A marvelous work of fiction" by people who flunked physics at high school.
Their basic belief is that there is a planet in a 3600 year orbit. They think it approached the sun, hiding behind it all the time so we couldn't see it, and then is suddenly going to jump out and hit us.
If anyone says this to you, then they immediately destroy their credentials as an astronomer.
Think about it. Can you see why it is impossible for a planet in a 3600 year orbit to be hidden behind the sun for years on end as seen from a planet with a one year orbit? It's not hard to see.
You don't need to know anything much except to understand what it means for a planet to orbit the sun. Don't need to know Kepler's laws or anything like that. This is a video I did to explain the concept for anyone reading this who hasn't yet learnt their astronomy "abc".
Another idea they have is that a planet would be visible in the daytime sky next to the sun.
They post images and videos like this
In this case Melissa Huffmann just asks what it is, she doesn't claim it is Nibiru. But many other videos like this are shared by people who just out and say it is Nibiru.
Notice that she can zoom in and it magnifies in place like a real object.
Do you know what this is? I'll give the explanation soon but meanwhile you might enjoy being pleasantly baffled :).
Anyway whatever it is, it can't be a planet or moon. This shows the Moon during a partial eclipse.
As you can see, the Moon itself is completely invisible. It's not lit up by the sun because the sun is behind it. You can see how this works for yourself, if you just use a table lamp, hold an orange between it and yourself, and you will see the dark side of the orange.
The Moon is behind the clouds and behind the scattered blue of the sky. And is completely black against a black sky, if you were to look at it, say, from space. So you don't expect to see it.
So again if someone thinks they can photograph a planet next to the sun, fully illuminated, and so close that it is the same visible size as the sun, or indeed of any size at all, then you know they haven't yet learnt their "astronomy abc".
It is no shame to have not learnt this stuff. I haven't learnt my "football abc" don't have a clue how the game works. It just shows you have never looked into the topic in any detail, not interested, or somehow missed out on it. Unless you are a journalist - if you are about to publish a news story about Nibiru - do run it past an astronomer first!
The only way something could be as close to the sun as this and also visible in the sky and as large as this, and show a full disk, is if it is a source of light itself - a second sun. Or - an absolutely huge sphere larger than the sun on the far side of the sun - but surely nobody thinks that's credible!
It's easy to prove for yourself that we don't have a second sun.
MANDATORY STARE AT SUN WARNING
Don't stare at the sun to see if you can see Nibiru. Newton stared at the sun for an experiment and he lost some of his vision for a fair while. Eventually he got it back but you might not be so lucky - some people get permanent vision loss in this way.
The radiation that damages your eyes is mainly UV light - and this is not visible. So even if the sun looks dim, behind clouds for instance, you don't know if it is safe without a UV light detector. Infrared also harms your eyes especially if viewed through binoculars or a telescope. And there are no pain receptors in your retina - and the damage often shows up only some time later - you may think everything is fine but then gradually lose vision.
Just don't do it. It is reasonably safe when the sun is right at the horizon with a flat open horizon - which is why people don't lose vision staring at a beautiful sunrise or sunset - but even then best not to stare for long.
So don't stare at the sun. But just block it out with your finger. Then, do you see another sun next to the sun? No? Then you have disproved this idea that there is a second sun visible in our sky, which some of the Nibiru believers think. Some of them believe it is not just a planet, but an entire separate solar system consisting of a sun with several planets, hiding behind our sun, but from time to time visible next to it.
They may explain to you that it is only visible for a short while before sunset, or after sunrise. But that doesn't make sense either. If there is a second sun in the sky next to the sun, then it is next to the sun for all observers, wherever you are in the world, and however high the sun is in your sky. Even if it is locally midday.
And a satellite wouldn't be visible next to the sun, for the same reason that a moon can't be, because it would be lit from the other side. The only way to see a satellite close to the sun, as for the moon in eclipse, is to watch it crossing the sun as a shadow.
Video of the ISS as a shadow crossing the sun, similar to the moon when it eclipses the sun but much smaller.
So - since it's not a second sun or a planet - what did Melissa Huffman make a video recording of?
EXPLANATION OF MELISSA HUFFMAN'S VIDEO BY MICK WEST
Mick West has looked at her video carefully, recently, and come up with an explanation.
First, he stabilized her video, as you can see here:
If you look at it carefully you can see that her sun sized "planet" is actually moving slightly relative to the clouds. Not nearly as much as the obvious lens flare, but in the same direction. So it can't be a sun mirage but has to be something much closer to the camera.
He then showed that you can get the same effect by putting a sheet of glass in front of a camera at an angle. So it would be easy to hoax a video like this.
This doesn't mean her video is a hoax - it could easily be that it's a result of misthreading a filter on the camera. Or a result of taking the video through a window.
If you engage the threads incorrectly, at an angle, then the glass of the filter will be at an angle to the lens, and then you'll get this effect. He shows that with a cross thread on his own camera which causes a similar double sun, complete with photo of the effect.
Cross threaded filter - easy to do when you put it on in a hurry - causes a similar double sun effect. Photo by Mick West
Just as with her video, when you zoom in on the image, it expands. And is sharp and clear like hers.
It is easy to check something like this if it happens to you. You can do the same test as for lens flare, put your finger in front of the sun and it will disappear - that is unless it is behind a window, in which case, just open the window.
Also if you rotate the camera then it will move if it is a cross threaded filter. It only stays in the same place in the sky if you keep the camera reasonably vertical all the time.
He goes into details here: Explained: Two "Suns" Sanibel Causeway, Florida [Offset Lens Reflection]
Many of the videos and photos are of lens flares. Since some lens flares move and others don't, or not so much, it is easy to think that the one that doesn't move is "real" but it isn't.
It is easy to test for lens flares.
As he says, so many people get fooled by this. Some are probably intentional hoaxes, some confused, in any case they don't have a clue.
ANOTHER NUTS IDEA - A PLANET ONLY VISIBLE FROM THE SOUTH POLE
Another idea that's often shared is the idea that Nibiru is only visible from the south pole, and sometimes they claim that NASA has built a special telescope in Antarctica to watch it.
Again if anyone says this, you know they haven't learnt their astronomy abc, and you can safely disregard anything they say about astronomy.
Just as the pole star is visible from most of the entire northern hemisphere, the southern cross is visible from most of the southern hemisphere.
Anything visible in the night sky above the South Pole would also be visible in Australia, New Zealand, Southern Africa, South America, etc. That is, unless it is actually hovering above the South pole almost in the Earth's atmosphere.
Another idea that comes up so often is that Nibiru is predicted by ancient astronomers.
They certainly could have had advanced philosophical ideas. But as for maths and astronomy - no, doesn't seem likely that they ever had advanced far in those fields.
First their maths - though advanced for their time - was rubbish by modern standards. The Sumerians, amongst the most advanced mathematically in the entire ancient world, had this clumsy way of thinking about ratios. They couldn't write 7/10 - for some reason had never thought of the idea of "seven tenth parts" in maths. Instead they would write it as 1/2 + 1/5. I.e. a half and a fifth. Imagine trying to multiply two ratios in that system! Even adding ratios is tricky. They didn't have negative numbers yet, or zero, or logarithms, or hardly any maths at all by modern standards. So were severely handicapped if they ever needed to calculate anything in astronomy.
Also -they didn't know that the Earth was a planet - that was a way out idea suggested by one Greek astronomer. They thought meteorites came from volcanoes, or possibly picked up by strong winds. They thought comets were in the atmosphere, a bit like clouds.
They didn't know about Ceres and Vesta, both of which are visible in the night sky if you know where to look, as very faint stars they could have seen on a dark night. As is Uranus which was plotted as a faint star, several times in different positions on night sky maps before it was shown to be a planet.
They didn't know about the moons of Jupiter. If you hide Jupiter with something, say behind a building, a keen eyed astronomer can see its moons. So in theory they could have spotted them, but never did.
So how could the ancient astronomers know about the even fainter Neptune (on the very edges of visibility- theoretically possible for a very keen eyed astronomer in perfect conditions) and even Pluto which is never naked eye visible?
If you think that they were told about this by extra terrestrial astronomers visiting Earth - then why did they not tell the Sumerians about the moons of Jupiter or Saturn's spectacular rings?
Saturn, with three of its moons, Tethys, Dione and Rhea from top to bottom.
Or tell them that the moon is cratered? When Galileo turned his telescope to the moon he expected to see a perfectly smooth sphere, the craters were a great surprise to him.
And don't you think we'd have picked up a bit of maths from them - at least some simple ideas like ratios or negative numbers or zero?
This is not to show any disrespect for ancient texts. It is just that astronomy is not their strong point. Except for occasional observations such as observations of supernovae which we can now interpret.
Yes they could predict solar eclipses by observing patterns to them. But they could never have produced a map like this:
So why expect ancient astronomers to be able to predict things we can't predict ourselves?
WHERE CAN PLANETS HIDE IN OUR SOLAR SYSTEM
So - can we have planets hiding in our solar system?
Well - actually, no, not inside of Pluto at least. Because we'd have found them by now.
ORBITS NOT STABLE
Planets in long period orbits that take them into the inner solar system are unstable. We get comets in orbits like that, but that's because there are millions of comets out in the Oort cloud. For planets to come into the inner solar system we'd need a similar reservoir of millions of planets out there.
Comets in long period orbits that cross the paths of several planets are unstable - their orbit keeps changing. They can't keep in a stable resonance with all the planets they pass by. Eventually they will probably hit a planet (usually Jupiter), or the sun, or be ejected from the solar system - or they get their orbits perturbed into something more circular.
Even objects in a circular orbit can't stay there for long unless they are in the asteroid belt or in special situations like the trojan points, sixty degrees ahead or behind a planet in its orbit. Anywhere else, then the nearest planet will "clear them from its neighbourhood". All the objects that currently fly past Earth - several a day - will be gone within around 20 million years.
We probably had extra planets in the early solar system - and lost them through collisions and ejecting from the solar system.
LIMITS ON PLANETS
We actually have searched carefully for planets inside of Mercury. Nothing there. Back in the nineteenth century they thought there might be a planet called Vulcan there because of perturbations of other planets and searched very carefully - but it was eventually disproved through Einstein's general relativity which explained the perturbations in a different way.
NASA has observed the sun from all directions with its two Stereo A and B satellites.
They came to the conclusion that there are probably no vulcanoids larger than 5.7 km in diameter, and no more than 76 of them larger than 1 km in diameter.
WHAT ABOUT BROWN DWARFS
Nibiru enthusiasts often say that it is a brown dwarf. They seem to think that brown dwarfs are invisible.
So - a brown dwarf is just a very large planet like Jupiter. It is hotter than Jupiter because it had nuclear fusion in its core when it first formed, but never quite made it as a star.
So- yes they are far more visible in infrared because they are hotter than Jupiter. But they are not invisible!
They can be very dark. But the Moon also is dark, as dark as worn asphalt - it looks bright in the night sky because there is no sun to compare it with.
A brown dwarf would be roughly same size as Jupiter (as gas giants get more massive than Jupiter they get denser but not much larger).
Jupiter's albedo is 0.343. So a brown dwarf at the distance of Jupiter would be about a seventh of the brightness of Jupiter.
Given those albedos we need to find how much dimmer it is than Jupiter in apparent magnitude. As usual I'll indent the calculation to make it easy to skip.
One magnitude corresponds to multiplying by 2.512 (fifth root of 100) for historical reasons.
So to find the magnitude of the darkest possible brown dwarf by reflected light at the distance of Jupiter, its dimmer by a factor of 0.343/0.05, or 6.86
So we want to find x such that (2.512)^x = 6.86. So x log(2.512) = log(6.86) so x= log(6.86) / log (2.512) or 2.09. So it would be 2.09 magnitudes fainter than Jupiter
So the darkest brown dwarf, at the distance of Jupiter would have apparent magnitude 2.09-1.6 (as stars get fainter the magnitude increases) or 0.49.
So the darkest brown dwarf, if at the distance of Jupiter when it is furthest from the Earth, would be roughly equivalent in brightness to Betelgeuse, top left star in the shoulder of Orion.
Deep sky image of Orion by Mouser. Betelgeuse is the red star at top left. It has apparent magnitude 0.42, close to the apparent magnitude 0.49 of the darkest possible brown dwarf at the distance of Jupiter at its furthest.
So, no, we couldn't miss a brown dwarf, even in visible light.
This wide field of view infrared telescope did several full sky surveys and could spot a planet by the change in position between images.
Artist's impression of the NASA Wide-field Infrared Survey Explorer. Researchers proved that Nemesis and Tyche can't exist in results published in 2014, using data that it collected in 2010 to 2011.
It gives strong constraints on a Jupiter or Saturn sized object. A Jupiter sized object must be at least 82,000 au from the sun, and a Saturn sized object at least 28, 000 au. But a brown dwarf can actually be similar in size to Jupiter and also very cold and as well as that, it can be much darker than Jupiter in appearance (though not invisible in reflected light, - our Moon is as dark as worn asphalt and of course, easy to see).
It's not too surprising that our solar system turns out to have no companion star, not even a red dwarf - the majority (54%) of sun type stars are single.
Brown dwarfs are less common than they used to be thought to be. As a result of the WISE survey again, it's now thought that there are six normal stars for every brown dwarf.
So, though it is becoming increasingly unlikely, apparently it would be possible for a small, dark and very cold five billion year old brown dwarf to be in our solar system at a distance of 26,000 au, even closer than the limit for Saturn. But that's no use for Nibiru. That's 650 times the distance to Pluto, or 0.41 light years away - so far away it would take light over 21 weeks to get from the brown dwarf to Earth.
LIMITS ON INVISIBLE PLANETS
Okay, there is no way a planet can be invisible. But perhaps a mini black hole? Those are very rare also because otherwise we would see stars blinking out in the night sky (a star is a much larger target than a planet) - and may not exist at all as they would have to be formed during the Big Bang according to current theories. A more normal black hole would be easy to see, through its accretion disk.
But even that can't exist in our inner solar system, not one of any size. Anything smaller than the Moon would be unstable, soon disappear through Hawking radiation - at least according to current theories. But those could be wrong.
Or - could it be a "dark matter planet"? Made of matter that only interacts weakly with ordinary matter?
Anyway - so how large an object could there be inside of, say, Saturn's orbit, and not be detected yet, supposing it is somehow totally invisible?
Well we have a spacecraft orbiting Saturn - Cassini - also many around Mars, and have long timelines for them also, so as a result we know the positions of those planets very exactly.
As a result then researchers have come up with Constraints on Dark Matter in the Solar System
By "dark matter" they include there all forms of matter we haven't detected yet including tiny asteroids or gas or dust.
It turns out that we are missing less than a seventh of the mass of Ceres. If there was even a hidden large asteroid there, it would have detectable effects on our spacecraft.
There can be extra planets in our solar system. But if so they have to be way beyond Pluto right now or we would know about them. Even dark matter planets, if such exist, or Moon sized or larger black holes would have to be way beyond Saturn.
Those planets may exist, and it's a fun and interesting subject in astronomy. See for instance Why This New "Planet X" Is No Threat To Earth :) about Mike Brown's most recent Planet X idea - one of the best candidates for a long time.
And we also are detecting many planets around other stars every year. But none of them are any threat to Earth.
Do comment if you have any questions. I'll put some of the newer material in this article into the new version of my Nibiru booklet when I get time to work on it.
For more on this see my "Imaginary Bullshit Planet" Nibiru - Lens Flares, Sun Mirages, Hoaxes&Just Plain Silly - with long comments thread with a lot more info.
Get notifications of new blog posts
If you want to get alerts every time I do one of these posts, join my Robert Walker - Science20 Blog Alerts facebook page.
To get a red facebook alert every time I post a new science20 article, or post an idea for a new article, then select "all on" in the page's Liked drop menu above.
Or subscribe to the associated twitter feed.
For email alerts about once every month or so, subscribe to Robert Walker's Science 20 blog Monthly Alerts on Google Groups.