Assume that the planet is so distant or otherwise separated that you are above all reasonable doubt certain that no contact will ever be established between it and Earth. You, your descendants or anybody else on Earth will never know anything about the new planet except the initial information that it exists and in one point of its history, it had one billion happy people.

To avoid the massive utility of knowing that another intelligent species survived the great filter you might want to specify that a 93rd planet full of reasonably happy people has just been located millions of light-years away.

The reason why I am asking is that I don't terminally value other people whom I don't directly know. I am still disturbed by learning about their suffering and I may value them instrumentally as bearers of cultural or linguistic diversity or for other reasons, but I am not sad if I learn that fifty miners have died in an accident in Chile, for example. I am a moral nihilist (I think that morality reduces entirely to personal preferences, community norms or game theory, depending on the context) and thus I accept the lack of intuitive sadness as good indicator of my values. According to LW standards, am I evil?

I think that given our evolutionary origins it's quite normal to have stronger feelings for people we know personally and associate ourselves with. All this means is that humans are poor administrators of other people's happiness without special training. You may try thinking about how you would feel if you had a button that collapsed a mine in Chile if you pushed it. Would you push it on a whim just because miners dying in Chile doesn't necessarily make you sad or would you suddenly feel a personal connection to those miners by means of the button you had to control their fate? What if you had to push a button every day to prevent the mine from collapsing? You might find that it isn't so much your emotional/moral detachment from miners in Chile but your causal detachment from their fates that reduces your emotional/moral feelings about them.