Why are you so sure there is no meaning of life? We cannot know it, because we do not know everything about the world.
Maybe we just did not find it yet? It's not inside the knowledge we have, so it might be beyond it. To find it, we may need to expand our knowledge about the world, i.e., do science. This is how science may (temporarily) replace the meaning of life.
And you don't have to be a scientist yourself. Instead you may help it in any way you like: spreading knowledge in humanity, preventing conflicts, providing necessary services, etc.
Maybe we just did not find it yet? It's not inside the knowledge we have, so it might be beyond it. To find it, we may need to expand our knowledge about the world, i.e., do science. This is how science may (temporarily) replace the meaning of life.
And you don't have to be a scientist yourself. Instead you may help it in any way you like: spreading knowledge in humanity, preventing conflicts, providing necessary services, etc.