Space and astronomy news
Gravitational lensing provides an opportunity to see supernovae and other transients much farther than we normally can. A new research proposal outlines a plan to use a comprehensive catalog of strong gravitational lenses to capture these rare events at extreme distances.
Continue reading “We can Probably Find Supernovae Enhanced by Gravitational Lensing, We Just Need to Look”
A star that sounds as if it came from “The Lord of the Rings” now marks one of the Hubble Space Telescope’s farthest frontiers: The fuzzy point of light, known as Earendel, has been dated to a mere 900 million years after the Big Bang and appears to represent the farthest-out individual star seen to date.
Based on its redshift value of 6.2, Earendel’s light has taken 12.9 billion years to reach Earth, astronomers report in this week’s issue of the journal Nature. That distance mark outshines Hubble’s previous record-holder for a single star, which registered a redshift of 1.5 and is thought to have existed when the universe was 4 billion years old.
The newly reported record comes with caveats. First of all, we’re talking here about a single star rather than star clusters or galaxies. Hubble has seen agglomerations of stars that go back farther in time.
“Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together,” lead author Brian Welch, an astronomer at Johns Hopkins University, said today in a news release. “The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc.”
A close look at the arc turned up several bright spots, but the characteristics of the light coming from Earendel pointed to a high redshift, which translates into extreme distance. The higher the redshift, the faster the source of the light is receding from us in an ever-more-quickly expanding universe.
Continue reading “A New Record! Hubble Detects an Individual Star From a Time When the Universe Was Less Than a Billion Years Old”
In the history of science and physics, several scholars, theories, and equations have become household names. In terms of scientists, notable examples include Pythagoras, Aristotle, Galileo, Newton, Planck, and Hawking. In terms of theories, there’s Archimede’s “Eureka,” Newton’s Apple (Universal Gravitation), and Schrodinger’s Cat (quantum mechanics). But the most famous and renowned is arguably Albert Einstein, Relativity, and the famous equation, E=mc2. In fact, Relativity may be the best-known scientific concept that few people truly understand.
For example, Einstein’s Theory of Relativity comes in two parts: the Special Theory of Relativity (SR and the General Theory of Relativity (GR). And the term “Relativity” itself goes back to Galileo Galilee and his explanation for why motion and velocity are relative to the observer. As you can probably tell, explaining how Einstein’s groundbreaking theory works require a deep dive into the history of physics, some advanced concepts, and how it all came together for one of the greatest minds of all time!
Continue reading “What is Einstein’s Theory of Relativity?”
It’s been seventy years since physicist Enrico Fermi asked his famous question: “Where is everybody?” And yet, the tyranny of the Fermi Paradox is still with us and will continue to be until definitive evidence of Extraterrestrial Intelligence (ETI) is found. In the meantime, scientists are forced to speculate as to why we haven’t found any yet and (more importantly) what we should be looking for. By focusing our search efforts, it is hoped that we may finally determine that we are not alone in the Universe.
In a recent study, two researchers from the University of Liège and the Massachusetts Institute of Technology (MIT) recommended that we look for evidence of transmissions from our Solar System. Based on the theory that ETIs exist and have already established a communications network in our galaxy, the team identified Wolf 359 as the best place to look for possible interstellar communications from an alien probe.
Continue reading “If Alien Probes are Already in the Solar System, Maybe we Could Detect Them Calling Home”
E.T. managed to call home with a Speak and Spell, buzzsaw blade, and an umbrella. The reality of interstellar communication is a bit more complicated. Space is really, really big. The power needed to transmit a signal across the void is huge. However, rather than using super high power transmitters, recent research by Stephen Kerby and Jason T. Wright shows that we could make use of a natural signal gain boost built into solar systems – the gravitational lensing of a solar system’s star. Networking a series of stars as nodes could get signals across vast tracts of the Milky Way. And we may be able to detect if our Sun is already part of an alien galactic communication network.
A stunning new photograph from the Hubble Space Telescope shows a nearly perfect Einstein Ring, an effect caused by gravitational lensing. This is one of the most complete Einstein Rings ever seen.
Continue reading “What a Perfect Gravitational Lens”
It is hard for humans to wrap their heads around the fact that there are galaxies so far away that the light coming from them can be warped in a way that they actually experience a type of time delay. But that is exactly what is happening with extreme forms of gravitational lensing, such as those that give us the beautiful images of Einstein rings. In fact, the time dilation around some of these galaxies can be so extreme that the light from a single event, such as a supernova, can actually show up on Earth at dramatically different times. That is exactly what a team led by Dr. Steven Rodney at the University of South Carolina and Dr. Gabriel Brammer of the University of Copenhagen has found. Except three copies of this supernova have already appeared – and the team thinks it will show up again one more time, 20 years from now.
Continue reading “Astronomers saw the Same Supernova Three Times Thanks to Gravitational Lensing. And in Twenty Years They Think They’ll see it one More Time”
Gravitational-wave astronomy is very different from that of electromagnetic light. While gravitational waves are faint and difficult to detect, they also pass through matter with little effect. In essence, the material universe is transparent to gravitational waves. This makes gravitational wave astronomy a powerful tool when studying the universe. But it’s still in the early stages, and there is much to learn about how gravitational waves behave.
Continue reading “It Could be Possible to see Gravitational Wave Lenses”
The Gaia spacecraft is an impressive feat of engineering. Its primary mission is to map the position and motion of more than a billion stars in our galaxy, creating the most comprehensive map of the Milky Way thus far. Gaia collects such a large amount of precision data that it can make discoveries well beyond its main mission. For example, by looking at the spectra of stars, astronomers can measure the mass of individual stars to within 25% accuracy. From the motion of stars, astronomers can measure the distribution of dark matter in the Milky Way. Gaia can also discover exoplanets when they pass in front of a star. But one of the more surprising uses is that Gaia could help us detect cosmic gravitational waves.
Continue reading “Gaia Might Even be Able to Detect the Gravitational Wave Background of the Universe”
One of the biggest challenges to measuring the expansion of the universe is the fact that many of the methods we use are model-dependent. The most famous example is the use of distant supernovae, where we compare the standard brightness of a Type Ia supernova with their apparent brightness to find their distance. But knowing the standard brightness depends upon comparing them to the brightness of Cepheid variables which is in turn determined by measuring the distances of nearby stars via parallax. Every step of this cosmic distance ladder depends upon the step before it.
Continue reading “A new Technique Could use Quasars to Directly Measure the Expansion Rate of the Universe”