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Creation 31(2):54–55, March 2009

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A lesson from Pluto

Image NASAPluto

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Pluto orbits 40 times further from the sun than Earth, and for over 70 years it has been regarded as the ninth planet of our solar system. Clyde Tombaugh (1906–1997) discovered Pluto in 1930 by comparing photographs of stars taken two weeks apart at the Lowell Observatory in Arizona.1

Lowell Observatory ArchivesClyde W. Tombaugh at the door of the Pluto discovery telescope, Lowell Observatory, Arizona.
Clyde W. Tombaugh at the door of the Pluto discovery telescope, Lowell Observatory, Arizona.

Because of perceived irregularities in the motion of Uranus, Percival Lowell (1855–1916), the founder of the observatory, believed in the existence of a ninth planet. He dubbed it Planet X and calculated that it would be six times more massive than Earth. He even specified its location.2 Lowell searched for the planet without success from 1906 until he died.

Tombaugh was hired by the observatory in 1929 and discovered the planet near where Lowell suggested. This apparently vindicated Lowell’s predictions so the discovery was appropriately announced on Lowell’s birthday (13th March) and the first two letters of Pluto’s name are his initials.3

Pluto is so faint that it can only be seen with a telescope 30 cm (12 in) or larger, and astronomers were unable to determine its size and mass. Early estimates could rely only on the deviations of the orbits of Neptune and Uranus. The size was quickly revised down from Lowell’s estimate, and eventually astronomers settled on a mass about three quarters that of Earth.

All this changed around 1978, nearly 50 years after Pluto’s initial discovery. The key evidence was found by James Christy of the US Naval Observatory when he realized that Pluto has a moon. He noticed that some of the images from their 1.5 metre telescope showed Pluto slightly elongated but the stars in the same photographs were not. From those images he was able to estimate the diameter of the moon’s orbit and its orbital period. As a result astronomers could calculate the mass of Pluto with far more certainty.4 It is now accepted that Pluto is only 1/500th the mass of the earth. Ongoing observations confirmed Pluto’s moon, and the International Astronomical Union gave it official status in 1985 and named it Charon.5

Above sentiment from Gray, R., Pluto should get back planet status, say astronomers
Richard Gray expressed the above sentiment in “Pluto should get back planet status, say astronomers”, published at telegraph.co.uk, 10 August 2008.

With such a tiny mass, Pluto could not possibly have affected the orbits of the gas giants Uranus or Neptune. In 1983 astronomers searched the entire sky by the Infrared Astronomical Satellite but no hidden planet was found. It is now generally believed that the perturbations to the orbits of Uranus and Neptune were imaginary, that Lowell’s calculations were wrong, and Tombaugh’s discovery was a coincidence.1

How could so many scientists be so wrong for so long about the mass of Pluto—by a factor of 400? A similar question is often asked when creationists speak of the earth being only 6,000 years old instead of the generally accepted age of 4,600 million years.

All the scientists got the same wrong answers because they all used the same models and the same assumptions.

The mass of Pluto, like the age of the earth, has not been measured directly. It is calculated from scientific models that are all based on assumptions. All the scientists got the same wrong answers because they all used the same models and the same assumptions. However, ongoing observations of the behaviour of Pluto led to more information that enabled an entirely different approach to the problem, overturning the previous assumptions and coming up with a radically new and soundly-based estimate.

There is another big difference. The mass of Pluto is operational science, where we can continue to make observations in the present using newer and better instruments and technology. But the age of the earth is historical science. We cannot travel back in time to make observations of things that only happened in the past. For information about the past we need reliable reports from eyewitnesses.

Pluto contradicts the nebular hypothesis

Pluto belongs to a class of objects that orbit the sun beyond Neptune, called TNOs (Trans Neptunian Objects). Astronomers regard these as material left over from the gas and dust nebula from which the solar system supposedly formed, supposedly 4.6 billion years ago.

But Pluto is a problem for the nebular hypothesis. First, it does not orbit in the same plane as the other planets (i.e., the ecliptic) but at an angle of 17°. Why not? Second, its axis of rotation is not perpendicular to its orbital plane but tilted so that it points almost directly at the sun at present. How come? Third, Pluto’s orbit is not circular but highly elliptical. In fact, it occasionally comes closer to the sun than Neptune. Why? These features of Pluto contradict the predictions of the nebular hypothesis, so astronomers have had to invent ad hoc secondary stories to explain them. So much for the nebular hypothesis.

Pluto and its moons1 don’t support the idea of billions of years either. Analysis of light from Charon suggests that its surface is covered with active volcanoes of ammonia-rich water spewing out of the moon’s deep interior. Similar conclusions have been reached for many TNO’s. This means there must be a source of internal heat within these objects. But if they are billions of years old they should have been cold and dead billions of years ago.

  1. Apart from Charon, two smaller moons, Nix and Hydra, were discovered in 2005.

References and notes

  1. Abell, G.O., Morrison, D. and Wolff, S.C., Exploration of the Universe, 6th edition, Saunders College Publishing, Philadelphia, USA, p. 186, 1993. Return to text.
  2. Ref. 1, p. 185. Return to text.
  3. Ref. 1. The name is from classical mythology and was suggested by Venetia Burney, an 11 year old school girl from Oxford, England. Return to text.
  4. Using Newton’s formulation of Kepler’s third law. Return to text.
  5. Ref. 1, pp. 288–289. Return to text.

Helpful Resources

Readers’ comments

Nicholas S.
As we all know, remarkably, Pluto has every two orbits of our Sun, exquisitely timed respective to Neptune's three orbits and timed to never collide with Neptune. Certainly requiring the demands of reasonable logic and precise, congruous design. Did Pluto manifest into our Solar System at an orbital plane of 17 degrees to the orbital plane of the other planets, by its own volition and also to not ever collide with Neptune, by Pluto's own self determination? Even our domestic pet rock can't think for itself. Revealed as a given and also wonderful, how Pluto does not comply with the nebular hypothesis and yet Pluto certainly exists. Nebular hypothesis: again revealed to be untenable and unrealistic. Again, actual true discoveries refute assertions made by abstract evolution theory.
Only God can, by His *Superior Reasoning Power, Create Pluto and its moons, having placed it and sent it on its correct trajectory, correct velocity and precise orbital plane, orbiting our Sun, Psalm 19:1, Romans 1:20. *As Albert Einstein explained: "the necessity for a beginning," and "the presence of a *Superior reasoning power" required for this atom structured, three dimensional, fine tuned universe to come into being. Reasoning: i.e. of Thought, i.e. of God, Hebrews 11:3.
As God obviously had a Plan for Pluto to exist and orbit our Sun for His Good, Precise Purposes, even if to refute evolution, in the future, then He Definitely, Absolutely has a Good, Precise Plan for each and every one of us Human Beings. All we have to do is have Faith and Believe, John 3:16, and follow His Will, Jeremiah 29:11-13. Spiritually rich and in Truth. Thank you CMI, for the timely reminder of how questionable and problematic nebular hypothesis is and ultimately incongruous with operational science.
Nicholas S.
Pluto did not fit the abstract evolution theory nebular hypothesis, it was then said by those theorists, Pluto came from outside our Solar System. Even though it has two orbits of the Sun, timed respective to Neptune's three orbits; timed never to collide with Neptune while crossing it's orbit; have a moon, Charon, with a gyroscope effect with Pluto which subsequently wobbles in its trajectory, however, phenomenally maintains elliptical orbit. Abstract evolution then says Pluto did this by its own 'self determination'. Our domestic pet rock can't think for itself. What is abstract evolution doing with Pluto's atmosphere of nitrogen, carbon monoxide and methane? Smudge them, with its elbow, off evolution's whiteboard of criteria required of a celestial body to be recognisable as a planet? Move the goalpost definitions of a planet, another several 'billion' 'years' away? An incoming object, from outside our Solar System, either likely spirals into the Sun or leaves the Solar System and cannot achieve a balanced orbit. There is no 'sweet spot'. Only God can reasonably place Pluto and send it on its correct trajectory, correct velocity and its balanced perihelion and aphelion elliptical orbit around our Sun. The Planets, including our Earth's complexities, our Sun, our Galaxy and all Galaxies, are all interdependent upon each other, so all are in formation and positioning reliance, for their existence. All had to be Created within a very short time frame. Six days is ideal, Genesis 1:1-31. As God obviously had a Plan for Pluto to exist and orbit our Sun for His Good, Precise Purposes, then he definitely, absolutely has a Good, Precise Plan for each and every one of us Human Beings. All we have to do is Believe, John 3:16, and follow His Salvation Will, Jeremiah 29:11-13.
Thomas R.
Question: Does physics dictate that an orbiting object’s path becomes more and more circular (round, as in constant radius), and less and less elliptical, around its host over time?

If so, calculations could be made to approximate upper and lower limits on how long a planet would have been in its orbiting state to produce its current orbital shape. Or at least how many orbits (or years) it would take to approach a circular orbital path.

Many thanks and God bless for considering this question.
Tas Walker
That's a good point. Another feature of planets is tidal locking, and that can be used to make an age estimate. Our moon is tidally locked with the earth, which is why one side always faces the earth.
David J.
Excellent, brief concise article, easily understandable. I re-started a discussion with a nephew about the age of the earth. I think author's paragraph following helps me succinctly state what I may have been less clear about in the past. CMI keep up the great and much-needed work!. "There is another big difference. The mass of Pluto is operational science, where we can continue to make observations in the present using newer and better instruments and technology. But the age of the earth is historical science. We cannot travel back in time to make observations of things that only happened in the past. For information about the past we need reliable reports from eyewitnesses."
Dan B.
It's hard to overstate the humbling effect of historical facts like these as Dr Walker sets out so well. Humbling, that is, for anyone who claims a final figure for anything as little-explored as Pluto was in 2009. Remarkably, since 2015, it's been perfectly clear that the *age* of Pluto also needs to come down by a similar factor, 400 or so, even as an upper limit. Devastating!

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