Preparations:
Click [You must be registered and logged in to see this link.] to download Nebula Stock.
Click [You must be registered and logged in to see this link.] to download the planets.

Quote :

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Disclaimer: and i am not the owner.

Step 1 - Setting Up Background:
Create a document of size 750×550 pixels.
Find the Red Nebula in the resource pack and resize it to fit into the document.
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Step 2 - Position the Planets:
We will need one small planet and another larger one.
Let’s name the small planet as Planet 1 and the other as Planet 2.
Overlap the two planets in manner shown in the diagram.
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Step 3 - Adjusting Colors:
Create an Hue/Saturation Adjustment Layer above all these layers.
Check on Colorize and key in 24 for Hue, 50 for Saturation and 0 for Lightness.
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Step 4a - Creating Explosion:
Create a new layer and name it as Yellow Flame.
Set your foreground color to #F7F61C and use Soft Brush tool to paint around the bottom of Planet 1.
Using the Smudge tool, pull out the left and right corners of the yellow paint as shown in the diagram.
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Step 4b - Creating Explosion:
Select the Eraser tool and set mode to Brush and type to Dry Brush.
Remove edges of the Yellow Flame with Eraser tool of various brush sizes. Blur some of the parts with the Smudge tool.
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Step 4c - Creating Explosion:
Create a new layer and name it as Orange Flame.
Set your foreground color to #FE9005. Repeat the same as Step 4a and 4b.
Go to Filter > Blur > Gaussian Blur and set the blur radius to 5px.
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Step 4d - Creating Explosion:
Create a new layer and name it as White Flame.
Set your foreground color to #FFFFFF. Repeat the same as Step 4a, 4b.
Go to Filter > Blur > Gaussian Blur and set the blur radius to 3px.
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Step 4e - Creating Explosion:
Now we have to blend all these flame layers together.
Set the Blend Mode of Orange Flame to Hard Light.
Right-click on White Flame and choose Blending Option. Activate Outer Glow and set the Blend Mode to Screen, color to #F9F900, Spread to 5px and Size to 20px. The rest remain as default.
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Step 5a - Adding Cracks:
Create a new layer and name it as Cracks.
Use Soft Brush tool of size 5px and color #FFFFFF, draw some irregular lines above the flames.
Remove some parts of the lines with Soft Eraser tool.
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Step 5b - Adding Cracks:
Right-click on Cracks and choose Blending Options.
Activate Outer Glow and set the Blend Mode to Linear Dodge (Add), Opacity to 100%, color to #FFFFBE, Spread to 0 and Size to 7px. The rest of settings remain as default.
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Step 6a - Adding Lens Flare:
Create a new layer and name it as Flare.
Fill this Flare layer with #000000. Go to Filter > Render > Lens Flare. Set the lens type to be 50-300mm zoom and position the flare as shown in the diagram.
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Step 6b - Adding Lens Flare:
Resize the Flare layer with Free Transform tool.
Rearrange the order of the layers such that Flare is just below the flames layer. Position the lens flare to the center of the flames.
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Step 6c - Adding Lens Flare:
Set the Blend Mode of Flare layer to Screen.
Duplicate the Flare layer and set the Blend Mode of the new layer to Color Dodge. Duplicate this new layer once more to brighten the flare further.
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Step 7a - Glowing Bits:
Create a new layer and name it as Glow Bits.
Set the foreground color to #FFFFFF and use Soft Brush tool of various sizes, paint some dots around the flames.

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Step 7b - Glowing Bits:
Duplicate the Glow Bits layer.
With the Smudge tool, pull a trailing tail out of each dot towards the flame as shown in the diagram.

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Step 8a - Add Flying Rocks:
Extract out some rocks of various sizes and place them around the document.
You may refer to this post for some methods on extraction.

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Step 8b - Add Flying Rocks:
Duplicate one of the rocks layer.
Go to Filter > Blur > Motion Blur. Set the Angle to 0 and Distance to 180px.

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Step 8c - Add Flying Rocks:
Select the blurred rock and go to Edit > Transform > Distort to adjust the shape into the one shown in the diagram.
Right-click on the original rock layer and choose Blending Options.
Activate Gradient Overlay and set Blend Mode to Multiply, Opacity to 100%, Gradient to Black,White, Scale and Angle depending on the size of your rock.
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Step 8d - Add Flying Rocks:
Activate Outer Glow and set Blend Mode to Overlay, Opacity to 100%, Noise to 0 , Color to #FFFFFF, Spread to 0 and Size to 20px. The rest of settings remain as default.
Activate Inner Glow and set Blend Mode to Normal, Opacity to 60%, Noise to 0 , Color to #000000, Spread to 0 and Size to 25px. The rest of settings remain as default.

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Optional:
You may repeat Step 8 for as many rocks as you desire as long as it looks good. I also created a Levels Adjustment Layer to enhance the depth.

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you :D