The European Radio Astronomy Club frequencies, the ionosphere is opaque. Here, two targets are possible: the Sun with its solar flares or Jupiter, which is also a very strong radio source, together with the moon Io, which is a very powerful natural radio wave transmitter. When Jupiter, Io and the Earth are aligned, it is possible to hear this radio source very clearly. The European Radio Astronomy Club The European Radio Astronomy club (ERAC) is Europe's only group coordinating the work of radio astronomers to jointly use radio waves to study the universe at radio wavelengths. It was founded in 1995 by Peter Wright, who
Atmospheric entry often travelling quite fast relative to the Earth simply because their own orbital path is different from that of the Earth before they encounter Earth's gravity well. Most controlled objects enter at hypersonic speeds due to their suborbital (e.g., intercontinental ballistic missile reentry vehicles), orbital (e.g., the Soyuz), or unbounded (e.g., meteors) trajectories. Various advanced technologies have been developed to enable atmospheric reentry and flight at extreme velocities. An alternative low velocity method of controlled atmospheric entry is buoyancy which is suitable for planetary entry where thick atmospheres, strong gravity, or both factors complicate high-velocity hyperbolic entry, such as the