New Earth

Start a new document 600x600. Set the foreground and background to Blue and White.

Then Go to Filter->Render->Clouds

Then go to Filter->Sketch->Note Paper.

Image Balance: 35
Graininess: 0
Relief: 25

You can play around with the image balance to get the shapes of your continents.

Use the circular marquee tool and make a round selection as big as you can on the image. Hold down shift while making the selection ensures you get a perfect circle.

Then go to Filter->Distort->Spherize

Amount: 100%

Then Edit->Copy

Then CTRL+N to create a new document.

The newly created document size should be left as is because photoshop will use the size of the copied image, else, just create a new document about 650x650.

Then in the new document, go to Edit->Paste to paste the image onto the new document.

You should now have a globe on white background.

Add a 1 pixel stroke to the image.

If you want to learn how to create stars, See the simple stars tutorial

A little bit of modification, I came up with this.

Download final .psd file To see the extras I did.