Researchers say life-bearing planets may exist in vast numbers in the space between stars in the Milky Way, the Science Daily reported Thursday.

A few hundred thousand billion free-floating life-bearing Earth-sized planets may exist in the space between stars in the Milky Way. So argues an international team of scientists led by Professor Chandra Wickramasinghe, director of the Buckingham Center for Astrobiology at the University of Buckingham, the U.K., according to the report.

The scientists have proposed that these life-bearing planets originated in the early Universe within a few million years of the Big Bang, and that they make up most of the so-called "missing mass" of galaxies.

The scientists calculate that such a planetary body would cross the inner solar system every 25 million years on the average and during each transit, zodiacal dust, including a component of the solar system's living cells, becomes implanted at its surface.

The free-floating planets would then have the added property of mixing the products of local biological evolution on a galaxy-wide scale, the Science Daily said.