New study deepens the controversy over Planet Nine's existence

Astronomers release new data to challenge claims about the mysterious Planet Nine.

New study deepens the controversy over Planet Nine's existence

Artist's impression of Planet Nine. Neptune's orbit is the small ellipse around the Sun.

Credit: Tomruen
  • University of Pennsylvania astronomers used Dark Energy Survey data to challenge the existence of Planet Nine.
  • Planet Nine was proposed to inhabit the outer reaches of our solar system, past Neptune.
  • The new data shows numerous smaller objects in that part of space but maybe no new planet.

Is there a mysterious Planet Nine hiding in the outskirts of our solar system? While there've been hypotheses making such claims, a new study looks to disprove its existence.

The research from astronomers at the University of Pennsylvania strikes at the heart of the clues that led some to believe such a planet was there. From 2014, astronomers have been suggesting various explanations for the behavior of so-called "trans-Neptunian objects" (eTNOs) that are farther from the Sun than Neptune. These rocks in the outer reaches were previously found to be clumped together, traveling in an elongated orbit, as reports New Scientist. One reason for that could be that they were pulled by the gravity of a giant planet that is five to 10 times the mass of Earth. One fascinating idea proposed about such a possible planet is that it may be responsible for the extinction of the dinosaurs, as it knocks catastrophic comets towards Earth when it passes through the Kuiper belt once every 27 million years.

The new research shows, however, that there may not be any clustering trans-Neptunian rocks at all. The scientists used data from the Dark Energy Survey, carried out at a Chilean observatory.

The University of Pennsylvania astronomer Pedro Bernardinelli, the lead author of the paper, thinks their data doesn't bode well for Planet Nine's probability.

"We would not have formulated the Planet Nine idea if our data was the only data that existed," said Bernardinelli to New Scientist. The scientist's previous 2020 study, also using data from the Dark Energy Survey, found 316 trans-Neptunian objects, including 139 minor planets in the space past Neptune. The researcher's works ultimately seems to show that the faraway region is inhabited by numerous small objects which are uniformly distributed rather than grouped.

While the scientists write that their data does not "require a "Planet 9" hypothesis," they nonetheless admit that "The limited sky coverage and object count mean, however, that the DES data by no means falsify this hypothesis."

How ‘The Goblin’ may unravel the mystery of Planet Nine

Samantha Lawler from the University of Regina, Canada, who was not involved in the study, also thinks there's still a chance the Planet Nine could still be out there. "The way that the Planet Nine hypothesis is constructed is that it's completely impossible to falsify it — the only way to prove it's not there is to search every square centimeter of the sky and not find it," she commented to New Scientist.

Read the new paper now at arXiv.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.


Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

Study helps explain why motivation to learn declines with age

Research suggests that aging affects a brain circuit critical for learning and decision-making.

Photo by Reinhart Julian on Unsplash
Mind & Brain

As people age, they often lose their motivation to learn new things or engage in everyday activities. In a study of mice, MIT neuroscientists have now identified a brain circuit that is critical for maintaining this kind of motivation.

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Why not just divide the United States in slices of equal population?

The contiguous U.S., horizontally divided into deciles (ten bands of equal population).

Image: u/curiouskip, reproduced with kind permission.
Strange Maps
  • Slicing up the country in 10 strips of equal population produces two bizarre maps.
  • Seattle is the biggest city in the emptiest longitudinal band, San Antonio rules the largest north-south slice.
  • Curiously, six cities are the 'capitals' of both their horizontal and vertical deciles.
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Surprising Science

Scientists discover why fish evolved limbs and left water

Researchers find a key clue to the evolution of bony fish and tetrapods.

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