The answer to 'why is my light fixture sparking' is that there is likely an electrical issue that needs to be addressed. Sparking in a light fixture can be caused by a variety of problems, such as a loose connection, damaged wiring, or a faulty component in the fixture itself.
Sparking can be a serious safety hazard, so it's important to address the issue promptly. If you're comfortable working with electricity, you can try to troubleshoot the problem yourself. However, if you're not confident in your electrical skills or the sparking is severe, it's best to call a licensed electrician to inspect and repair the fixture.