My Bible doesn't mention Carl Sagan. It does, however, warn about judging others.
I'm not judging anybody. I'm not discussing my standards--they're God's. Those standards are called the Ten Commandments. Can you say that you have always kept all ten of them, have never broken one of them? I know that I can't. I don't feel bad about saying that to you because I know that you can't, either.
Let's just do a quick test, shall we?
Have you ever told a lie? If so, you're a liar.
Have you ever stolen anything (small or great)? If so, you're a thief.
Have you ever used God's Name as a curse word? If so, you're a blasphemer.
That's just three of them (there are seven others), and if you're like me you can't honestly say that you have kept those three for your whole life, either. That makes you guilty before God, and destined for hell. Doesn't that prospect frighten you? It should.
On the day of your judgement, you will be measured against God's standards and found wanting. That is why you (like the rest of us) need a Savior. There is only One, and His Name is Jesus.
I Corinthians 5:10 covers the fact that Carl Sagan most likely knows God's truth by now, whether or not those who are still living believe it. The only way that he doesn't is if the proper understanding of scripture is that Mr. Sagan is in a waiting situation until we all face God at one time.
As for judging others, I would be curious to know what it is in your copy of the Bible that leads you to believe that we are not allowed to know right from wrong when we see them. The only times I've ever heard anyone try to argue that "judging others" was sinful was when they took Matthew 7:1 out of the Bible because it suited their purpose, of trying to silence those who recognized their sin, and denied almost the entirety of the rest of the Bible. Using the same type of so-called logic and the same level of intellectual honesty you could just as well declare that it is a sin to split wood. "What God has put together, let no man put asunder." You can take any scripture in the Bible or any other book of any religion or any human creed of evolution or...well you get the idea... choose a choice phrase that you think makes a point that you want made and completely ignore the reality of what the text you pulled it from says. Congratulations you now qualify to be a mainstream journalist by todays standards. However if you want to have some intelligent discourse with people who will respect you enough to consider what you say, you would be far wiser to stick to your chosen texts rather than warp them in that way (and just not choose a book that doesn't really make the point you want made).
What precisely does your Bible tell you about judging others?
Most people quote a certain passage about judging others but have no concept of what it means other than throwing a "Bible verse" at someone with whom they disagree to demonstrate their "knowledge" of scripture.
The judgement warning is the single most misused quote of the Bible simply because it is used by so many to justify their own failings rather than to judge that which is unholy as to compared to what is Holy.