gravitational force with the energy derived from the nuclear fusion. If a giant star of tens of solar masses consumes the nuclear fusion-derived fuel completely, it can no longer endure its self-weight, resulting in collapse. Super large gravitational forces cause distortion in the surrounding space-time, making it impossible for any substance or material (even light) to go out. A black hole is considered to be formed in this way. In outer space where stars are distributed in a high density, the thus-formed black holes merge with each other, gradually growing in size to become giant black holes of more than million solar masses. If one of such supermassive black holes takes up the surrounding stars into it one after another, there arises a spiral of the residues and gases from the crushed and heated stars around the black hole, leading to the formation of a brightly shining disc. This disc, with brightness comparable to that of the entire galaxy composed of 100 billion stars, is visible as a celestial object called an “active galactic nucleus (AGN).” AGN is sometimes accompanied by a pair of narrowly focused flows of plasma, which are 100 thousand light-years long and are called a “jets.” The jets are flows of plasma created by a giant black hole, moving at a flow rate close to the light speed. The jets flowing in the inter-galactic space gradually decreases in speed, eventually forming a drift called “radio lobe.” The radio lobe spans 100 thousand light-years. If investigated in detail, this lobe provides information about the substances/materials carried outwards by the jet and the total energy, thus giving hints to understanding of the one million-year history of AGN. Radio lobe serves as a source of strong radio waves and simultaneously emits X-rays. This fact was unveiled by our observation in 1995 using the Japanese X-ray astronomy satellite “ASCA.” If the data from observation of radio waves are combined with the data from observation of X-rays, we may obtain a useful hint to clarification of total energy of electrons and magnetic fields. Because the plasma constituting the radio lobe gives energy to the space-filling residual light of the big bang (cosmic microwave background radiation), resulting in generation of X-rays, we can measure the electron energy through the X-rays. At the same time, since the electrons produces radio waves with the weak inter-galactic magnetic field, we can estimates the field strength by observing radio waves. The radio lobes archives the AGN history described with the jets. We are attempting to clarify how the space was formed as we see through tracing the history of AGN and its jet by studying the radio lobe at diverse stages of evolution.