The Bottomless Pit is not Hell or Hades, the place of abode of the Spirits of wicked men and women until the resurrection of the Wicked Dead.

            Neither is it Tartarus the Prison House of the fallen angels in Jude 6-7, nor the Lake of Fire, the final hell in Matthew 25:41.

            But it is the place for the demons, who are not Satan's angels but a group of disembodied spirits. They are wicked, unclean, vicious and have power to derange both mind and body.

                  They are Familiar Spirits and the Seducing Spirits that Paul warned Timothy about in 1 Timothy 4:1.

The work of both Angels is the same, to unlock and lock the bottom-less pit.

           It doesn't seem reasonable that God would entrust the Key of the Prison House of the demons to a Fallen Angel or even to Satan himself.

John said that he saw the descent of the star, or angel and it descended so rapidly that it appeared to be falling.

         This is the same Star Angel that comes down from heaven, having the key of the bottomless pit and a great chain in his hand, and binds Satan and casts him into the pit.

                 So it's clear that the star angel isn't Satan.

When the Fifth Trumpet sounded, John saw a star fall from heaven.
 
          That it was not a literal star is clear because the star in the next verse is spoken of as a person [He], in the Old Testament angels were called stars.

                  Because the star was fallen from heaven doesn't mean that it was a fallen angel, or Satan as some have thought.

Fifth Trumpet
First Woe
The Plague of Locusts
Revelation 9:1-12

"And the Fifth Angel sounded, and I saw a star fall from Heaven unto the earth: and to him was given the key to the bottomless pit.
And he opened the bottomless pit, and there arose a smoke out of the pit, as the smoke of a furnace; and the sun and the air were darkened by reason of the smoke of the pit.
And there came out of the smoke locusts upon the earth: and unto them was given power, as the scorpions of the earth have power.
And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.
And to them it was given that they should not kill them, but that they should be tormented five months: and their torment was as the torment of a scorpion, when he striketh a man.
And in those days shall men seek death, and shall not find it: and shall desire to die, and death shall flee from them.
And the shape of the locusts were like unto horses prepared unto battle: and on their heads were as it were crowns of gold, and their faces were as the faces of men.
And they had hair as the hair of women, and their teeth were as the teeth of lions.
And they had breastplates, as it were breastplates of iron; and the sound of their wings was  as the sound of chariots of many horses running to battle.
And they had tails like unto scorpions, and there were stings in their tails: and their power was to hurt men five months.
And they had a King over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon. One woe is past; and, behold, there come two woes more hereafter."

The Angel Warning
Three Woes Announced
Revelation 8:13

"And I beheld, and heard an angel flying through the midst of heaven, saying with a loud voice, woe, woe, woe, to the inhabiters of the earth by reason of the other voices of the Trumpet of the three angels, which are yet to sound."

What happens under the Fourth Trumpet is similar to what happened under the Sixth Seal.

          These are some of the Signs spoken of by Jesus in Luke's Gospel that precedes His Second Coming.

                     The signs in the Sun, and in the Moon, and in the Stars and upon the earth distress of nations with perplexity.

Never forget 911

Fourth Trumpet
Moon and Stars Smitten
Revelation 8:12

"And the Fourth Angel sounded and the third part of the Sun was smitten and the third part of the Moon and the third part of the Stars; so as the third part of them was darkened and the day shone not for a third part of it, and the night likewise."

Wormwood is an herb, very bitter and is used in the manufacture of Absinthe.

          It is used a lot in France as a beverage and is more intoxicating and destructive than ordinary liquors.

                 This is foretold by a Prophet named Jeremiah. "Therefore thus saith the Lord of Hosts, because they have forsaken my law, Behold, I will feed them, even this people (Israel)  with wormwood and give them water of gall to drink."
Jeremiah 9:13-15.

When the Third Trumpet sounded a great star fell from heaven burning like a lamp.
           
            This could be another meteor that will look like a torch on its path through the heavens and when its gaseous vapors are scattered as it explodes, they will be absorbed by the third part of the rivers and fountains of waters and be poisoned and made bitter and many men shall die from drinking the water.

Third Trumpet
The Star Wormwood
Revelation 8:10-11

"And the Third Angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, and upon the fountains of waters; and the name of the Star is Wormwood: and the third part of the waters (rivers) became wormwood, and many men died of the waters, because they were made bitter."

One third of the ships will be destroyed also, possibly by a tidal wave, or the meteor may fall on a fleet of navel vessels.

The only difference between the First Egyptian Plague and the effect on the Mediterranean Sea by the falling meteor into it at the sounding of the Second Trumpet, will be that only one third of the sea will become blood and only one third of the living creatures in the sea will die.

A Great Mountain is to fall on the sea, and the Judgments that pour from the Trumpets and Vials are to fall mainly on the part of the world bordering the Mediterranean Sea, and it's possible that the Sea mentioned is the Mediterranean Sea.

       John doesn't say that it was a Mountain that he saw cast into the sea, but that it appeared like a mountain, not a burning volcano, but a huge meteor mass ablaze with fire.

               That was as near as John could describe it. Its effect was to turn a third part of the sea into blood. Much like the Plague in Exodus 7:19,21.

Second Trumpet
The Burning Mountain
Revelation 8:8-9

"And the second Angel sounded, and as it were a Great Mountain burning with fire was cast into the sea: and the third part of the sea became blood; and the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed."

In Egypt the hail smote every herb of the field and every tree, but in the First Trumpet only one-third of the trees and grass will be burnt up.

The difference between the Egyptian Plague and the one John describes is, that in Egypt man and beast suffered with the vegetation, with only the trees and the green grass suffering when the First Trumpet sounds, and the hail and fire will be mingled with blood.