I'm new to UE4 and this branch in general. So I have no idea how to fix this . your help would be appreciated
In order to obtain the best result for your project, there is basically two ways:
- Make your own 3D models from scratch with a 3D software like Blender (free)/ Maya LT/ 3DS Max.
- download free 3D models from various websites (I personally do not rely on this solution so I don't know if these websites will be good, but you can always download models from Clara.io or CGTrader).
If you want to make the 3D Model from scratch, you will need to model the Rings of Saturn and unwrap the UVs (that's the main problem in your result), and either create the texture from scratch (with Blender, Substance or another Texture Software) or apply the texture that you've uploaded here.
Please note that your current texture of the Rings of Saturn will be displayed in Unreal Engine, but it is definitely not the right format in the gaming industry (i.e., the resolution of your file is not a Power of Two like 256*256 or 1024*1024). The various reasons of keeping a Power of Two texture might not ring a bell at this stage but should be kept in mind (mip-maps, no GPU optimization, no multi-plaform game support...).
Good luck with your Solar System project!