Can I deduct start up costs after my first year of business?

Basically, its a business but I haven't earned income for it yet. However, I know I can deduct $5,000 my first year and the rest over 15 years (amortized) as long as it is no more than $50K. But I haven't earned income when I started the business and I want to know if I can deduct my start up costs in later years?