Happy Sabbat of Azathoth! Come on, different planets would experience May 1 at different 'times' anyway.
I want to talk more about "objective morality". Because while I mentioned it briefly in a previous argument, the word "objective" could have two different meanings here.
First, it could mean that we can prove a moral position objectively (inter-subjectively, if you want to get technical). Clearly, none of us have an objective morality in this sense. You can prove that a given action will have a given result, but this doesn't get us anywhere unless we already accept some definition of morality.* When people talk about reason proving moral claims, either they haven't thought it through, or they want to appeal rhetorically to some part of the listener that agrees with their definition (as I do when arguing for my preferred rules of behavior).
I have a bit more trouble rigorously expressing the second possible sense of the word "objective". I'll give it a shot. Sometimes, people who use the term appear to mean that morality exists in the noumena. (And not just in other humans considered as noumena, but somewhere else entirely.) For the reasons previously stated, this view logically implies that something like a definition of morality exists 'outside' of all humans. When I try to make sense of this curious claim, I arrive at the image of a non-human intelligence that happens to agree with the speaker. This roughly agrees with the views of Aristotle and especially Plotinus.
I freely admit that my morality (if you want to call it that) does not claim any objective origin in this second sense. I maintain that nobody else gets morality from outside themselves either, except in the sense that my will comes from "outside myself". (Namely, in the sense of efficient cause rather than formal cause. Y'all make decisions using your inner morality, and would continue to do so if I somehow proved that your 'outer source of morality' wanted you to rape and kill.**) And I argue that "objective" formal origin would not add any morally significant benefit in any case, whether we use my definition of morality or Nate's. Consider Azathoth. The Great God of the Old Ones who sits at the Center of Infinity closely resembles Aristotle's Prime Mover and Form of Good -- more than the Torah's YHVH does, frankly. ("For assuredly, does not the Unmoved Mover continue its own activity eternally with no thought for others? Therefore GLOMPSLUUURP" Old One eats your brain) But if we could prove that Azathoth produces and rules all reality, I still wouldn't feel morally compelled to imitate his priest Cthulhu, or others like Nyarlathotep who claim to speak for him. (Well, no more than I already do.) Likewise, if we could prove that the One or the Nous agrees with me, I wouldn't consider this logical proof of my morality. It would give me a nice feeling, but someone else with a different morality could continue as before with no self-contradiction. (Unless they invoked the authority of the One for some odd reason. And since LINAD, finding a contradiction in one opposing view would not prove my own definition.) In this situation, I'd consider the divine intelligence moral because it agrees with me, not the other way around. I argue that pretty much everyone shares this reaction (see first asterisk), unless they'd accept Azathoth as their personal savior. Theologians know this, more or less, and some have tried to address it by identifying their God with the Form of Good. I don't think this assertion changes the argument. Trying to assign a meaning to the words brings us quickly back to Azathoth, who creates our definition of morality along with everything else and inspires the alien morality of the Old Ones. (See also the non-dimensional King in Flatland by A Square.) I'd also like to point out that you couldn't get much farther removed from the first meaning of the word "objective".
*Technically, we don't need a verbal definition if we experience some reaction that assigns meaning to an event. (For example, a reaction that includes anger and makes us want to use the word 'evil'.) Instead of "a definition", I could have said "a complex of semapoetic reactions", but then nobody would have any clue what I meant.
**I don't mean to ignore the Pauline argument about God helping you to behave morally. That argument assumes you already have some fixed morality before experiencing direct non-human help. Otherwise it just begs the question.