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Latest: Planet Nine May Be a Primordial Black Hole

When anyone talks of Planet Nine, all of the space buffs out there get excited. This yet-to-be discovered and elusive planet has sparked many hot debates.

But, what if the so-called Planet Nine was not really a planet?

What if it was actually one of the oldest black holes that was created in our universe? These oldest black holes are often dubbed as Primordial Black Holes.

The problem is that the existence of Primordial Black Holes has neither been confirmed nor denied.

So, what is this Planet Nine and Primordial Black Hole debate all about? Let us find out…

What Really is Planet Nine?

Did you know that our solar system has what is known as eTNOs? eTNOs are nothing but extreme trans-Neptunian objects.

These eTNOs are space objects (or rocks, you may say) that lay beyond the planet Neptune and they orbit around the Sun.

That was fine until the astronomers went on to find that the orbit followed by these eTNOs is quite weird.

Did you know that the average distance of eTNOs from Sun is about 250 times more than the average distance of Earth from Sun?

The scientists found that these eTNOs, when they make their closest approach to our Sun, they all tend to stay approximately in just one region.

planet nine
By Tomruen – Own work, CC BY-SA 4.0, Link

On top of that, all these objects appeared to have similar tilted orbits. Such alignments are just improbable. Not all the eTNOs can behave in the same way.

Did you know that the extreme trans-Neptunian objects or eTNOs are the most distant known objects in our solar system?

This is where it was hypothesized that there was a planet (that is yet undiscovered) that is responsible for shepherding the orbits of eTNOs.

So, the idea of Planet Nine was born to explain the weird behavior of the eTNOs.

A Bit About Planet Nine

Your mind may be teemed with questions like, ‘how big is Planet Nine?’, ‘how far is it from Sun?’, ‘what role it has to play in case of eTNOs?’, etc.

We will answer these questions in brief.

According to all hypotheses, the Planet Nine has to be a super-Earth-sized planet. In numbers, Planet Nine is anywhere between 5 times and 15 times bigger than our Earth.

As far as its distance from Sun is concerned, it is hypothesized that the orbit of the planet is elongated and it lays at a distance 400 to 800 times as far from Sun as the Earth.

How was Planet Nine formed? According to Michael E. Brown (American astronomer) and Konstantin Batygin (Russian-American astronomer), Planet Nine is the core of a gigantic planet that was thrown out from its orbit by Jupiter when the solar system was being formed.

planet nine
By Corvus – Own work, CC BY-SA 4.0, Link

Some go on to propose that the planet was actually captured from another star. There are yet others who go on to say that Planet Nine was actually a rouge planet in one point in time and was later captured.

Again, there are other people who say that Planet Nine was formed on a completely different and distant orbit and a passing star managed to pull it into its eccentric orbit.

Irrespective of all the theories in place the search for Planet Nine has yielded nothing so far. Planet Nine remains mysterious and theoretical.

Not Planet Nine but Primordial Black Hole

A new research paper surfaced on arXiv on September 24, which states that the proposed Planet Nine could actually be a Primordial Black Hole!

According to scientists, Primordial Black Holes came into existence within the first second of the Big Bang that created the universe.

The existence of these Primordial Black Holes has not been confirmed and neither has the scientific community denied the existence of these black holes.

How big are these Primordial Black Holes? Not much! If these primordial black holes do exist, they won’t be any bigger than our popular baseball.

The New Research with OGLE Project

The scientists who posted the researched paper actually conducted an experiment over a period of 5 years. The OGLE project or Optical Gravitational Lensing Experiment project were aimed at finding optical gravitational microlensing events.

Gravitational microlensing is a method which is used by astronomers for detecting and discovering cold planets. We will discuss about gravitational microlensing in a separate article.

During the 5-year research, the astronomers involved noticed that there were 6 distinct events of microlensing.

These events can happen only when an object, which is about 0.5 times to about 20 times the size of Earth, acts as a gravitational lens.

So, the researchers said that instead of those objects being planets, they can be Primordial Black Holes.

The study says…

According to the researchers, the most accepted theory explaining the origin of Planet Nine is the capture of a free-floating planet. They went on the say that the research shows that instead of a planet, capturing of Primordial Black Hole is comparable.

Planet Nine or Primordial Black Hole – Batygin Speaks

Konstantin Batygin was one of the astronomers who was involved in the hypothesis of Planet Nine. However, this new research was conducted by Jakub Scholtz and James Unwin.

When Batygin was asked about the research, he said that yes, a Primordial Black Hole is definitely a possibility however, he did not seem to be very convinced about the whole research.

In an interview with Astronomy, Batygin stated that all the calculations can only tell about the mass of the Planet Nine but the composition remains unknown. So technically, Planet Nine, as long as its orbital parameters are right, can be anything. It can be a planet, it can be a black hole, it can be a hamburger or it can be a potato. Batygin says that he will prefer to keep an open mind.


So, what do you think? Is Planet Nine actually a planet or is it a Primordial Black Hole?

As far as the new research is concerned, the objects about the size of 0.5 times to 20 times the size of Earth are located somewhere around 26,000 light years away towards the galactic bulge of our Milky Way.

Possibly, they can quite easily correspond to a population of primordial black holes instead of just a bunch of free-floating planets.

Mysterious Universe
Las Cumbres Observatory