Short answer: philosophers disagree. There are plausible arguments on both sides, and no consensus. What follows is a quick guide to the main positions and the strongest reasons people give for each.

What people mean by “objective” vs “invented”
- Objective (moral realism): moral claims assert facts about the world that are true or false independent of what anyone thinks or feels. “Torturing children for fun is wrong” would be true even if everybody believed otherwise.
- Invented (moral anti‑realism/constructivism/relativism): moral claims reflect human minds, emotions, social practices, or conventions. They are true or binding only relative to attitudes, cultures, or constructed rational procedures.

Major positions (very briefly)
- Moral realism (non‑naturalist and naturalist forms): there are moral facts. Non‑naturalists see these facts as sui generis; naturalists try to reduce them to natural facts (e.g., well‑being, harms).
- Constructivism: moral truths are the product of rational procedures or practices (they are “constructed” by agents following certain rules), not mind‑independent Platonic facts.
- Error theory: moral talk attempts to state objective facts but always fails because there are no moral facts (J. L. Mackie).
- Expressivism/subjectivism: moral statements express attitudes or prescriptions rather than report facts; truth is not about mind‑independent facts.
- Cultural relativism: moral claims are true relative to cultural norms.

Arguments for objectivity
- Moral discourse behaves like factual discourse: we argue, cite reasons, claim to discover moral truth — this suggests moral beliefs aim at objective truth.
- Moral progress: talk of moral improvement (e.g., abolition of slavery) seems to presuppose standards that transcend any single culture’s conventions.
- Best‑explanation/inference to the best explanation: moral realism can explain the apparent stability and normative force of many moral claims.
- Some moral facts can plausibly be natural facts about suffering, flourishing, or justice, and thus are discoverable empirically.

Arguments against objectivity
- Cultural and historical disagreement: deep variation in moral norms suggests morality is shaped by culture, not by universal facts.
- Evolutionary and psychological accounts: our moral beliefs can plausibly be explained as adaptive responses, biasing us away from trusting them as revealing mind‑independent truths.
- The “queerness” or metaphysical difficulty (Mackie): positing non‑natural moral facts is ontologically odd and hard to make sense of epistemically.
- Hume’s is/ought problem: you can’t straightforwardly derive factual statements from purely descriptive facts, complicating any claim that moral truths are simply discovered empirical facts.

Middle-ground and pragmatic views
- Moral objectivity can be understood weakly (intersubjective): objective in the sense that properly idealized, rational agents would endorse certain norms.
- Moral skepticism: we might not know whether morality is objective, but we can still act on reasoned moral judgments and revise them on reflection (reflective equilibrium).
- Pluralism: some moral claims have greater objectivity (e.g., prohibitions on gratuitous suffering) while others are more contestable.

Practical consequences
- If morality is objective, then moral disagreement is a matter of error or ignorance; we should seek better reasons and evidence.
- If morality is invented or constructed, then deliberation, democratic institutions, and cultural change matter more in determining what we call “right.”
- Either way, taking reasons seriously and being open to revision is a defensible practical stance.

If you want to go deeper
- Read J. L. Mackie (Ethics: Inventing Right and Wrong) for the classic “invented”/error theory case.
- Read Derek Parfit (On What Matters) or Russ Shafer‑Landau (Moral Realism) for defenses of realism.
- Read Sharon Street on evolutionary arguments against moral realism, and Simon Blackburn or Gilbert Harman for expressivist/constructivist takes.

Bottom line
There’s no settled answer: strong, sophisticated arguments exist on both sides. How persuasive they are depends on how you balance explanatory power, metaphysical parsimony, and epistemic concerns. If you want, tell me which arguments appeal to you (intuitions? science? metaphysics?) and I can tailor a deeper discussion.
