Someone just contacted Earth, and it shouldn't have...because it is long dead

A sudden signal from space surprised astronomers when they found out that it came from a NASA satellite that had not been operational for almost 60 years. The brief, but extremely powerful signal was detected by radio telescopes in Western Australia. It came from Relay 2, a communications satellite launched by NASA in 1964. The signal lasted only a nanosecond, but was brighter than entire galaxies, New Scientist reported.

Relay 2 did its job only for about three years and went silent in 1967. NASA declared it dead, and nothing has been transmitted from it since then, until now. It witnessed a burst of activity, prompting a signal to reach Earth. Australian Square Kilometer Array Pathfinder (ASKAP), a network of 36 radio telescopes, picked it up. What led to a dead satellite emitting such a bright signal after all these years?

Scientists think that the satellite itself did not play any part in it, but was influenced by something else that happened in space. There is no confirmation on what it was. But there is a possibility that it suddenly released the energy it had been building up while orbiting through Earth's magnetic field. However, the external factor seems more likely.

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Astronomers believe that a micrometeoroid travelling at great speed hit the satellite, resulting in a burst of heat and charged particles that caused Relay 2 to emit the intense signal. What has surprised them even more is the fact that despite travelling so far, it remained extremely strong. It released about 400 watts of power at the time the event happened.

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The signal was similar to fast radio bursts (FRBs) that are typically emitted by pulsars and dead stars from deep space. So when Australian scientists noticed the high-energy flashes coming from somewhere so near, they could not believe it. Relay 2 is only about 4,500 kilometres above Earth's surface, well within the planet's orbit. They thought an unknown object, such as a pulsar, was travelling near Earth.

Dr. Clancy James, lead researcher and associate professor at Curtin Institute of Radio Astronomy, told New Scientist, "We thought we might've found a new pulsar or a never-before-seen object. Instead, we saw an incredibly powerful radio pulse that eclipsed everything else in the sky for a split second."

Scientists traced it back to the dead satellite that was passing overhead. The intensity of the radio signal was measured at more than three million janskys - 100 billion times stronger than the radio signals from a smartphone. Because of its strength and short duration, it was assumed to be coming from a cosmic object in deep space. A typical radio signal from a satellite lasts a microsecond (one-millionth of a second), but this was 1,000 times faster - the fastest and most powerful signal of its kind ever recorded near Earth.