As you drive down the road leading to the Jodrell Bank Observatory, a sign asks visitors to turn off their cell phones, saying the Lovell telescope is so powerful it can detect a phone signal on Mars.
Radio telescopes are designed to be extremely sensitive. To quote the legendary astronomer Carl Sagan, “The total amount of energy outside the solar system ever received by all radio telescopes on planet Earth is less than the energy of a snowflake hitting the earth.”
The total energy now probably costs a few snowflakes, but it is still true that astronomical radio signals are usually of magnitude smaller than artificial ones. If Jodrell Bank could pick up interference from a phone signal on Mars, how would it handle an entire 4G network on the moon?
This is a problem that worries astronomers like me after Nokia of America received $ 1
Radio frequency interference (RFI) is the long-term nemesis of radio astronomers. Jodrell Bank – the earliest observatory for radio astronomy in the world that still exists – was created due to RFI. Sir Bernard Lovell, one of the pioneers of radio astronomy, found his job in Manchester prevented by RFI from passing trams in the city and persuaded the university’s botany department to let him move to their fields in Cheshire for two weeks (he never left ).
Since then, radio telescopes have been built more and more remotely in an attempt to avoid RFI, with the upcoming Square Kilometer Array (SKA) telescope being built in remote areas of South Africa and Australia. This helps cut out very common sources of RFI, including cell phones and microwave ovens. However, terrestrial radio telescopes cannot completely avoid space-based RFI sources such as satellites – or future lunar telecommunications networks.
RFI can be attenuated at the source with appropriate shielding and signal transmission accuracy. Astronomers are constantly developing strategies to reduce RFI from their data. But this increasingly relies on the goodwill of private companies to ensure that at least some radio frequencies are protected for astronomy.
The long-term dream of many radio astronomers would be to have a radio telescope on the far side of the moon. In addition to being protected from terrestrial signals, it will be able to observe at the lowest radio frequencies, which on Earth are particularly affected by a part of the atmosphere called the ionosphere. Low-frequency observation can help answer basic questions about the universe, such as what happened in the first few moments after the Big Bang.
The scientific case has already been identified by the Netherlands-China low-frequency explorer, a telescope reconfigured by the Queqiao relay satellite sent to the moon in the Chang’e 4 mission.
It’s not just 4G
Despite its interest in these radio projects, Nasa is also looking at commercial partnerships. Nokia is just one of 14 US companies with which Nasa is working in a new set of partnerships worth more than $ 370 million to develop its Artemis program, which aims to bring astronauts back to the moon by 2024.
The involvement of private companies in space technology is not new. And rights and mistakes have been discussed for a long time. Probably the biggest attraction is SpaceX’s Starlink satellites, which caused a stir among astronomers after their first major launch in 2019.
The images quickly began to appear with traces of Starlink satellites cutting through them – often overshadowing or obscuring the original astronomical targets.
Astronomers have long had to deal with satellites, but Starlink’s numbers and brightness are unprecedented and their orbits are difficult to predict. These concerns apply to anyone involved in terrestrial astronomy, whether using an optical or radio telescope.
A recent analysis of the satellite’s impact on radio astronomy was published by SKA, which is developing the next generation of radio telescope technology for an array of square kilometers. It is estimated that SKA telescopes will be 70% less sensitive in the bandwidth that Starlink uses for communication, suggesting a possible number of 6,400 Starlink satellites.
As space becomes more commercialized, the sky is filled with a growing amount of technology. That is why it has never been more important to have provisions to protect astronomy. To make sure that as we take further steps into space, we will still be able to look at it from our home on Earth.
This article was republished from The Conversation by Emma Alexander, PhD in Astrophysics, University of Manchester under a Creative Commons license. Read the original article.
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