Viewed through a telescope, the planet Mars looks rust-red because rust is a large component of its soil.
Is this proper grammar??
Yes, it's good.
Thank you!
You're welcome.
Yes, the sentence "Viewed through a telescope, the planet Mars looks rust-red because rust is a large component of its soil." is grammatically correct.
To determine if a sentence is grammatically correct, you can check if it follows the rules and structure of the language. In this sentence, all the words are spelled correctly, the subject ("the planet Mars") and verb ("looks") agree in number, and the phrase "because rust is a large component of its soil" forms a coherent clause that provides additional information.
If you have further concerns about grammar, you can use online grammar-checking tools, grammar books, or seek assistance from a language expert or proofreader.