“The heavens declare the glory of God, and the sky above proclaims his handiwork. Day to day pours out speech, and night to night reveals knowledge. There is no speech, nor are there words, whose voice is not heard. Their voice goes out through all the earth, and their words to the end of the world. In them he has set a tent for the sun, which comes out like a bridegroom leaving his chamber, and, like a strong man, runs its course with joy. Its rising is from the end of the heavens, and its circuit to the end of them, and there is nothing hidden from its heat.” -Psalm 19:1–6
The word of nature is beautiful, objectively speaking. As Thomas Aquinas noted, beauty can be defined as that which possesses integrity, proportion, and clarity. The heavens beautifully declare the glory of God and all the sky above, which is seen by all human beings regardless of time or geographical place of existence, show off his indescribable creative prowess. God’s artistic proclamations are seen every single day. And, the sun, running its circuit every day without fail, is the greatest example of how brilliant, how loud, and how permeating his revelation of himself to man is.
St. Paul helps us get a sense of the gravity and importance of Psalm 19 in his letter to the Romans:
“For the wrath (Pure Justice) of God is revealed from heaven against all ungodliness (lit., lack of God consciousness) and unrighteousness (impious thoughts and behavior) of men, who by their unrighteousness suppress the truth (lit., hide the truth from themselves and others). For what can be known about God is plain to them, because God has shown it to them (see Psalm 19). For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived (ever seen the sun rise and set?), ever since the creation of the world, in the things that have been made. So they are without excuse.” -Romans 1:18–20
There is no legitimate or acceptable excuse for men who deny the existence of God and reject his Lordship over their lives and over the cosmos.
There is no excuse, either, for professed believers to live like those atheists.