“it’s ridiculous to say that eclipses are signs of God’s wrath. Is gravity a sign of his wrath?”
The wrath of God is already present. So, it isn’t hard to predict that wrath is coming. It’s already present. It’s just a matter of when it is going to be revealed. Wrath is the default condition for every human being because the whole world and every human by merely being human is the enemy of God.
John 3:36 NKJV
He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life, but the wrath of God abides on him.
Romans 1:18 NKJV
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness.
Romans 2:5 NKJV
But in accordance with your hardness and your impenitent heart you are treasuring up for yourself wrath in the day of wrath and revelation of the righteous judgment of God.
Ephesians 2:3 NKJV
Among whom also we all once conducted ourselves in the lusts of our flesh, fulfilling the desires of the flesh and of the mind, and were by nature children of wrath, just as the others.
1 John 5:19 NKJV
We know that we are of God, and the whole world lies under the sway of the wicked one.
The connection with the signs in the heavens is that God already gave these to mankind to set our calendars by. And these signs indicate when He will be paying a visit, or otherwise intervening in human history.
“Is gravity a sign of his wrath?”
No. But people go down into Hell, or up into Heaven. In the natural realm, people who ignore the force of gravity may put themselves and others in danger. They don’t know the gravity of the situation.
Psalms 55:15 NKJV
Let death seize them; Let them go down alive into hell, For wickedness is in their dwellings and among them.
John 3:13 NKJV
No one has ascended to heaven but He who came down from heaven, that is, the Son of Man who is in heaven.