The author does not support the idea that studyng Venus is a worthy pursuit despite the dangers it presents because he or she provides no explanation of facts stated and creates conflicting ideas that cast a grim shadow on travel to Venus.

First, the author doesn't support the idea effectively because he or she presents facts without explaining the significance or importance of them.

While describing why scientists consider visits to venus, the author states "Astronomers are fascinated by Venus because it may well once have been the most Earth-like planet in out solar system...The value of returning to Venus seems indisputable"(4).

By presenting that scientists want to visit Venus then almost immediately jumping to the weak conclusion that the "value of returning to Venus seems indisputable", the author fails to explain why the scientists want to visit Venus and why those reasons are important or significant.

Without an explanation of facts, writers leave the reader to create conclusions in their own minds, possibly without a complete understanding, weakening the authors support of his or her own claim or idea.

Second, the author doesn't support the idea effectively because he or she creates the picture in the reader's mind that successful and worthwhile travel to Venus is nearly impossible and certainly not attainable with today's technology.

While writing on what would be necessary for travel and observation of Venus, the author states "a vehicle hovering over Venus would avoid the unfriendly ground conditions...[and be] survivable for humans.

However, peering at Venus from a ship orbiting or hovering safely far above the planet can provide only limited insight on ground conditions...[Also,] standard forms of photography...[would be] innefective...Therefore, sciendtists seeking to...understand Venus would need to get up close and personal despite the risks"(5).

By stating that "a vehicle hovering over Venus" would be safe for humans and then directly stating that it would not be enough and that scientists who want useful information would have to "get up close and personal despite the risks", the author states conflicting ideas.

In addition, earlier in the passage the author states "On the planet's surgace, temperatures average over 800 degrees"(3).

This creates another serious flaw in the author's idea, because the conditions stated are not even close to survivable.

Combining the evidence presented by the author would point to the conclusion that astronomers would need to be using vehicles and photography equipment that currently don't exist and, even with unavailable technology, they must be willing to die to travel to Venus for study.

This creates the idea in the reader's head that studying Venus is impossible, which greatly weakens the author's claim.

All in all, impossibilities, conflicting ideas, and a lack of explanation of evidence crontribute to a weak argument in favor of the idea that studing Venus is a worthy pursuit despite the dangers it presents.