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Is Pluto a planet or not? Yes, it is and so are over 100 Celestial Bodies

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In this image of Pluto taken by NASA’s New Horizons spacecraft, different colors represent different compositions of surface ices, revealing a surprisingly active body. (Image: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute) VOA
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NEW YORK, March 18, 2017: Is Pluto a planet or not? Giving this debate a fresh angle, Johns Hopkins University scientist Kirby Runyon wants to make one thing clear: Regardless of what people say, Pluto is a planet.

So, Runyon says, is Europa — commonly known as a moon of Jupiter — and so is the Earth’s Moon and so are more than 100 other celestial bodies in our solar system that are denied this status under the prevailing definition of “planet”.

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The definition approved by the International Astronomical Union in 2006 demoted Pluto to “non-planet,” thus dropping the consensus number of planets in our solar system from nine to eight.

“The change – a subject of much scientific debate at the time and since – made no sense,” said Runyon, lead author of a paper set to be presented next week at a scientific conference in Texas.

Icy, rocky Pluto had been the smallest of the nine planets; its diameter under three-quarters that of the moon and nearly a fifth of Earth.

Still, says Runyon, Pluto “has everything going on on its surface that you associate with a planet. … There’s nothing non-planet about it”.

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Runyon led a group of six authors from five institutions in drafting a proposed new definition of “planet,” and a justification for that definition.

All the authors are science team members on the New Horizons mission to Pluto, operated for Nasa by the John Hopkins University Applied Physics Laboratory.

In the summer of 2015, the New Horizons spacecraft became the first to fly by Pluto, some 4.67 billion miles from Earth, passing within 8,000 miles and sending back the first close-up images ever made of Pluto.

Runyon and his co-authors argue for a definition of “planet” that focuses on the intrinsic qualities of the body itself, rather than external factors such as its orbit or other objects around it.

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They define a planet as “a sub-stellar mass body that has never undergone nuclear fusion” and that has enough gravitational heft to maintain a roughly round shape.

This definition differs from the IAU definition in that it makes no reference to the celestial body’s surroundings.

That portion of IAU’s 2006 formula – which required that a planet and its satellitesmove alone through their orbit – excluded Pluto.

Otherwise, Pluto fit the IAU definition: It orbits the Sun and it is massive enough that the forces of gravity have made it round.

The proposed new geophysical definition omits stars, black holes, asteroids and meteorites, but includes much of everything else in our solar system.

It would expand the number of planets from eight to approximately 110. (IANS)

 

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Astronomers building small space telescope to explore nearby stars

The telescope uses a mirror system with coatings optimized for ultraviolet light. Together with the camera, the system can measure very small changes in the brightness of M dwarf stars to carry out the primary science of the mission.

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The name of the stars which astronomers will study are called M-Dwarfs. Pixabay
The name of the stars which astronomers will study are called M-Dwarfs. Pixabay
  • Astronomers are building a space telescope to study the nearby stars.
  • the telescope will be small along with a camera attached to it.
  • Studying these nearby stars will help astronomers help study the way planets orbit around the stars.

Astronomers are in the process of building a small space telescope to explore the flares and sunspots of small nearby stars to assess how habitable the space environment is for planets orbiting them.

The telescope with a diameter of 9 centimetres, or 3.6 inches, will be fitted on a spacecraft known as the Star-Planet Activity Research CubeSat, or SPARCS to be launched in 2021, to focus on stars that are small, dim and cool by comparison to the sun.

Astronomers through this feat will be able study the path of planets.
Astronomers through this feat will be able study the path of planets.

These stars — known as M dwarfs — are less than half the sun’s size and temperature and they shine with barely one per cent of its brightness.

The telescope will be built alongside a camera with two ultraviolet (UV)-sensitive detectors to be optimised for observations using UV light, which strongly affects the planet’s atmosphere and its potential to harbour life on the surface.

“People have been monitoring M dwarfs as best they can in visible light. But the stars’ strongest flares occur mainly in the ultraviolet, which Earth’s atmosphere mostly blocks,” said Evgenya Shkolnik, Assistant Professor at the Arizona State University.

Although the orbiting Hubble Space Telescope can view stars at ultraviolet wavelengths unhindered, its overcrowded observing schedule would let it dedicate only the briefest of efforts to M dwarfs.

Telescope can view stars at ultraviolet wavelengths unhindered. Wikimedia Commons
Telescope can view stars at ultraviolet wavelengths unhindered. Wikimedia Commons

The telescope uses a mirror system with coatings optimized for ultraviolet light. Together with the camera, the system can measure very small changes in the brightness of M dwarf stars to carry out the primary science of the mission.

M dwarfs are exceedingly common that they make up three-quarters of all the stars in our Milky Way galaxy as well as nearly 40 billion rocky planets in habitable zones around these stars, meaning that most of the habitable-zone planets in our galaxy orbit M dwarfs.

Capturing lengthy observations of M dwarfs will let astronomers study how stellar activity affects planets that orbit the star. IANS