Is earth only a habitable planet?

 So far, Earth is the only planet in our known universe that is known to be habitable for humans and most forms of life as we know it.

While there are other planets in our solar system, such as Mars and some moons of Jupiter and Saturn, that have the potential to support life, they have not been found to have the same conditions and resources that are necessary for long-term human habitation.

Outside of our solar system, astronomers have identified a number of exoplanets, some of which are located in the "habitable zone" of their star, where the conditions might be suitable for liquid water and potentially life. However, as of yet, we have not been able to directly observe any signs of life on these planets, and much more research is needed before we can definitively say whether or not they are habitable.

So for now, Earth remains the only known habitable planet in our universe.