In "War of the Worlds" by Mike Brown, what is the author’s purpose, and what is his main argument to advance this purpose?

The author's purpose is to defend the title of the planet for pluto and name 2003 UB313 as the tenth planet in the solar system. He claims that this would help students see the universe as something that is always expanding and show how science is always evolving.

We can arrive at this answer because:

For him, Pluto must be kept as a planet and 2003 UB313 (which is bigger than Pluto) must be placed as the 10th planet of the solar system, as this would present the impression that the universe is expanding and this stimulates scientific progress.

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The author Mike brown's purpose is to bring to our attention the recent dilemma about the decision to declare or remove the planet Pluto as a valid planet. He believes that Pluto remains a planet and others are also declared as planets so that children and future generations will have the idea of explorations as an ongoing process.

His main argument was that if Pluto and 2003 UB313 are declared as full-fledged planets, then that will encourage children to believe in the possibility of future explorations and that they can also be a part of such adventures.  

Explanation:

Mike Brown's article "War of the Worlds" is an argumentative text on why space unions must accept the fact that Pluto and the newly discovered 2003 UB313. This is because if such discoveries are deemed invalid and not accepted, then there is no use for further explorations. Moreover, scientific studies have also already taken a backseat, which is detrimental to future generations who have an interest in the field.

But if such explorations are accepted, then the interest will remain and also give new birth to space studies. Moreover, it will also ensure that future exploration activities are done.

And in advancing his argument, Brown recounts his childhood fascination with space and how such a negative approach to accepting new exploration activities might hinder a child from having any interest in the scientific field. But "[d]oing so might convince schoolchildren to put new paper disks on their walls, to look up to the sky and realize that exploration does continue and that they can be part of it, too."