Answer:
Technology is defined by how people use scientific knowledge, and not only does scientific knowledge constantly change, but the way we use it is also constantly changing.
Emerging technologies refers to a new technology or technological innovations. The problem is that what can be considered new and how fast will it become obsolete? Our world is changing so fast, that current technology will be obsolete in just a few months, or maybe a year from now.
Because new technologies become old too fast, it is very difficult to identify them before they are no longer an innovation. Only those technologies that become mainstream can be clearly identified as emerging technologies, e.g. the iPhone was considered an emerging technology in 2007 and even though the first iPhone is obsolete now, it became mainstream technology.