Scientists are investigating strange blinking lights in the sky for indications that they are signs of "interstellar communication lasers" or alien structures.

A number of appearing and vanishing objects have been spotted among the stars and are puzzling the scientists who are trying to understand what they are.

Astronomers believe the lights will probably be coming from "natural, if somewhat extreme, astrophysical sources". But they are yet to find any explanation, after discovering 100 of the lights.

Whatever scientists find it likely to change our understanding of space, potentially ushering in a "new astrophysics", scientists said.

"The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilisations," the authors write in the new paper.

Nasa's groundbreaking decade of space exploration: In pictures Show all 10 1 /10 Nasa's groundbreaking decade of space exploration: In pictures Nasa's groundbreaking decade of space exploration: In pictures Mystic Mountain, a pillar of gas and dust standing at three-light-years tall, bursting with jets of gas from fledgling stars buried within, was captured by Nasa's Hubble Space Telescope in February 2010 Nasa/ESA/STScI Nasa's groundbreaking decade of space exploration: In pictures The first ever selfie taken on an alien planet, captured by Nasa's Curiosity Rover in the early days of its mission to explore Mars in 2012 Nasa/JPL-Caltech/MSSS Nasa's groundbreaking decade of space exploration: In pictures Death of a star: This image from Nasa's Chandra X-ray telescope shows the supernova of Tycho, a star in our Milky Way galaxy Nasa Nasa's groundbreaking decade of space exploration: In pictures Arrokoth, the most distant object ever explored, pictured here on 1 January 2019 by a camera on Nasa's New Horizons spaceraft at a distance of 4.1 billion miles from Earth Getty Nasa's groundbreaking decade of space exploration: In pictures An image of the Large Magellanic Cloud galaxy seen in infrared light by the Herschel Space Observatory in January 2012. Regions of space such as this are where new stars are born from a mixture of elements and cosmic dust Nasa Nasa's groundbreaking decade of space exploration: In pictures The first ever image of a black hole, captured by the Event Horizon telescope, as part of a global collaboration involving Nasa, and released on 10 April 2019. The image reveals the black hole at the centre of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides about 54 million light-years from Earth Getty Nasa's groundbreaking decade of space exploration: In pictures Pluto, as pictured by Nasa's New Horizons spacecraft as it flew over the dwarf planet for the first time ever in July 2015 Nasa/APL/SwRI Nasa's groundbreaking decade of space exploration: In pictures A coronal mass ejection as seen by the Chandra Observatory in 2019. This is the first time that Chandra has detected this phenomenon from a star other than the Sun Nasa Nasa's groundbreaking decade of space exploration: In pictures Dark, narrow, 100 meter-long streaks running downhill on the surface Mars were believed to be evidence of contemporary flowing water. It has since been suggested that they may instead be formed by flowing sand Nasa/JPL/University of Arizona Nasa's groundbreaking decade of space exploration: In pictures Morning Aurora: Nasa astronaut Scott Kelly captured this photograph of the green lights of the aurora from the International Space Station in October 2015 Nasa/Scott Kelly

In the research, detailed in a new paper published in the Astrophysical Journal, scientists looked at publicly available images of the sky dating as far back as the 1950s, such as old military sky catalogues. They compared those historical observations with modern sky surveys, looking for physical indicators that included stars that appear to have disappeared from the Milky Way.

"Finding an actually vanishing star – or a star that appears out of nowhere! – would be a precious discovery and certainly would include new astrophysics beyond the one we know of today", said project leader Beatriz Villarroel, Stockholm University and Instituto de Astrofísica de Canarias, Spain.

Usually, a dying star will change very slowly to become a white dwarf, or die with a sudden explosion as a supernova. A vanishing star would therefore indicate something else entirely: either a new, natural astrophysical phenomena or extraterrestrial activity elsewhere in the universe.

The only known natural explanation for such a vanishing star would be a "failed supernova", which has been theoretically predicted to be what happens when a very massive star collapses into a black hole, without sending out any kind of explosion. But those are very rare.

Possible extraterrestrial explanations include lasers being sent through the universe as part of communication between stars, or Dyson spheres, which are theoretical structures that alien civilisations could build around a star and harness its energy. While both are hypothetically possible, no evidence for either has ever been discovered.

Scientists have already look at 15 per cent of the possible candidate objects they have in their data, and found about 100 of the objects they called "red transients". Some of them are behaving very dramatically, flaring up to become several thousands times brighter very quickly.

"We are very excited about following up on the 100 red transients we have found", said Beatriz Villarroel in a statement.