They call it the Hadean period - the early life of the Earth from which even rock doesn't survive. So, it's long been assumed that the Earth was a molten rockball at this point.
The oldest rocks we do have are zircon crystals, some of which are more than four billion years old. And finally, it occurred to somebody to compare ancient zircon with recently-formed zircon. To do this, geologists went to Iceland, one of the most geologically active parts of the planet.
The conditions that formed the modern Icelandic zircon were worse (in terms of life) than those in which the ancient zircons formed. The environment they were created in were cooler and wetter. The early Earth may well have not looked so different from today. Or, it might have looked rather like, oh, this.