Written by Jason Petersen
One of the most commonly cited evidence for a young universe in the realm of astronomy are short period and long period comets. Comets can last a maximum of 11 million years, but if the solar system is only 4.6 billion years old, then there should be no more comets. This article will examine comets and how they don’t fit with an old earth worldview. It will also examine some of the common defenses of an old universe and show why those responses don’t hold water.
What are Comets?
The word “comet” comes from the Greek word “komhthcomètè “(long-haired), from which we also get the word “comb”.(1) Comets are icy masses that orbit the sun in space. They typically orbit in an elliptical path.(Planets have elliptical orbits as well, though many of them do look more circular.)
Comets typically lose some of their icy mass while orbiting the sun. This is why comets sometimes appear to have a tail. Eventually, after passing by the sun so many times the comet will completely lose its mass due to the rays from the sun. Comets can also deteriorate due to gravity from “nearby” planets. Because of the process of deterioration from the sun’s rays and gravity from other masses such as planets, comets don’t last forever.
How long do comets typically last?
How long comets last depends on their orbit. Those that have longer orbits will normally last longer than those who have shorter orbits around the sun. Comets don’t typically last more than 11 million years(This can be calculated by using Kepler’s third law of planetary motion.), though most don’t last for more than 500 orbits.(1) A famous comet(Known as Haley’s Comet) passes by Earth once every 76 years.(2) Haley’s Comet will last about another few tens of thousands of years.
The Age of the Solar System and Comets
If comets last no more than 11 million years, then how can they be around if the solar system is supposedly about 4.6 billion years old, how is it that we still have comets? After all, unless there is a supply of comets to replenish the solar system then we shouldn’t have any comets left!
Before we go further, we need to define what a rescuing device is. A rescuing device is a conjecture(An opinion or conclusion formed based on incomplete information.) that is used to save a worldview when confronted with evidence that is contrary to their worldview.
The Old Universe Worldview’s Rescuing Devices
1. The Oort Cloud: In 1950, an astronomer named Jan Oort proposed that the comets in the solar system came from a distant cloud of icy objects.(3) This is a hypothetical cloud that has never been seen. When someone points out to someone that long period(These are comets with orbits that take a long time to complete.) comets can’t last billions of years they will often say that the comets came from the Oort Cloud even though it has never been observed.(This is a rescuing device.) Such a notion that comets come from Oort Clouds is nothing more than a conjecture. Atheists and evolutionary apologists have no trouble believing that this Oort Cloud exists. So much for empirical evidence.
However, there is another issue aside from the fact that there is no evidence for the Oort Cloud. It is postulated that the way that comets are drug out of this “Oort Cloud” is by the gravity of passing objects causes those icy bodies in the Oort Cloud to “fall” into the solar system. However, a study that was done in 2001 shows another problem. It is said that comets are formed from left overs from the formation of planets. According to the theory, this icy material was sent out to the Oort Cloud in the outer reaches of the solar system by the gravity of the newly formed planets. All of the earlier studies ignored collisions between the comet nuclei during this process. This study has considered these collisions and has found that most of the comets would have been destroyed by the collisions. Thus, instead of having a combined mass of perhaps 40 Earths, the Oort cloud should have at most the mass of about a single Earth. It is doubtful that this is enough mass to account for the comets that we see.(4) The researchers postulate “escape valves” that could supply up to 3.5 Earth masses,(5) but this is still ‘low compared to estimates of the mass of the Oort Cloud. They then say that they think ANOTHER source in the region could supply comets to the Oort Cloud! They then claim that such a notion could resolve the problem for how the Oort Cloud obtains the comets to begin with.(3)
2. The Kupier Belt: The Kupier belt is a hypothesized source for short period comets(These take a shorter period to orbit the sun, usually less than 200 years.) The Kupier belt is a flattened disc that is said to have billions of icy bodies that are supposedly left over after the formation of the solar system.(5) This belt is said to exist beyond the planet Neptune. It is said that occasionally a passing object will pull one of these icy bodies out of the Kupier belt into the solar system where the icy body will now orbit the sun as a comet.
It’s important to note that Creationist scientists have always expected to find other icy and rocky bodies beyond Neptune. When main stream scientists started discovering these bodies that they now call the Kupier belt, Creationists were not surprised. However, the Kupiter belt, as it stands, does not solve the problem of short period comets. First, the Kupier belt would need around a billion icy bodies, so far we have not seen billions, the scope of the Kupier belt remains speculative. It should also be noted that the icy bodies discovered in the so called Kupier belt are significantly larger than comets. The diameter of the nuclei of a comet usually is about 10 kilometers. However, many of the bodies found in the Kupier belt are estimated to be between 100 kilometers and 500 kilometers in diameter. (6) These icy bodies are too large to be the prerequisite to nuclei based on the current model for comets in mainstream science. The size of these bodies calls their model into question. Of course, the only defense of their model is speculation which is void of any empirical evidence. They can call it the Kupier belt if they’d like, but it isn’t the type of “Kupier belt” that they are looking for to resolve the issues of how we can still have comets after billions of years.
Of course, if you accept that the universe is only about 6,000 to 10,000 years old, then this pesky problem disappears.
7. Featured photo credit: Wikipedia