HI everyone, let's explore a few things or thought about time travel.
Hyper velocity stars
Theorized in 1988, and observed in 2005, hyper velocity stars move faster than the escape velocity of the Milky Way, and are traveling out into intergalactic space. There are several theories for their existence. One of the mechanisms would be that the supermassive black hole at the center of the Milky Way ejects stars from the galaxy at a rate of about one every hundred thousand years. Another theorized mechanism might be a supernova explosion in a binary system. Intergalactic travel using these stars would involve entering into an orbit around them and waiting for them to reach another galaxy.
Artificially propelling a star
Another proposal is to artificially propel a star in the direction of another galaxy.
Possible faster-than-light methods
The wrap drive is a hypothetical concept that is able to impulse a spacecraft to speeds faster than light (the spaceship itself would not move faster than light, but the surrounding space it would). This could in theory allow practical intergalactic travel. There is no known way to create the space-distorting wave this concept needs to work, but the metrics of the equations comply with relativity and the limit of light speed.
A wormhole is a hypothetical tunnel through space-time that would allow instantaneous intergalactic travel to the most distant galaxies, even billions of light years away. Wormholes are allowed by general relativity.
Bengaluru: Astronomers have observed many ‘dead’ galaxies, but the process of the death itself hasn’t been observed before — until now.
Using the telescope Atacama Large Millimeter/sub-millimeter Array (ALMA), astronomers observed a galaxy, nine billion light years away from the Earth, ejecting nearly half of its star-forming gas and losing fuel.
Galaxies begin to ‘die’ when star formation stops inside them, or they start losing material that forms stars.
The ID2299 galaxy is currently ejecting material worth about 10,000 suns every year in the form of cold gas ejection. It is estimated that the galaxy is currently removing 46 per cent of the total cold gas it contains.
The galaxy is still forming new stars very rapidly, but since it is also quickly running out of fuel, the remaining gas will be consumed and the galaxy is likely to be dead within a few million years.
“This is the first time we have observed a typical massive star-forming galaxy in the distant Universe about to ‘die’ because of a massive cold gas ejection,” said Annamaria Publish, lead researcher of the new study from UK’s Durham University and the Sac lay Nuclear Research Center (CEA-Sac lay), France, in a statement.
Why ID2299 is ejecting gas
The research team behind the findings believes that the ID2299 galaxy is ejecting monumental amounts of cold gas because of a collision between two galaxies, which eventually merged to form ID2299.
Colliding galaxies are identifiable by their ‘tidal tail’ — elongated streams of gas and stars traced out in interstellar space behind the galaxies.
These tails are harder to spot in distant galaxies, but since the researchers caught the bright feature just as it was launching into space, they were able to identify that the gas ejection was a part of the trail.
It was previously believed that black hole activity as well as winds caused by star formation ejected the gases out of galaxies.
“Our study suggests that gas ejections can be produced by mergers and that winds and tidal tails can appear very similar,” said study co-author Emanuele DGDDI of CEA-Sac lay in the statement.
DGDDI I believe that retrospective analysis of gas ejections captured could confirm if some of them are in fact tidal tails.
“This might lead us to revise our understanding of how galaxies ‘die’,” he added.
The discovery was a serendipitous accident and occurred when the team was inspecting data from a galaxy survey conducted by ALMA to study the properties of cold gas in far away galaxies.
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