mick laBriola

Measuring the distance to truly remote objects like galaxies, quasars and galaxy clusters is a crucial task in astrophysics, particularly when it comes to studying the early Universe, but it’s a difficult one. Only in the case of a few nearby objects like the Sun, planets and some nearby stars can we measure their distances directly. Beyond that, various indirect methods need to be used; one of the most important is by examining Type Ia supernovae, and this is where the NASA/ESA Hubble Space Telescope comes in.

NGC 3810, the galaxy featured in this image, was the host of a Type Ia supernova in 2022. In early 2023 Hubble focused on this and a number of other galaxies to closely examine recent Type Ia supernovae. This kind of supernova results from a white dwarf exploding, and they all have a very consistent brightness. That allows them to be used to measure distances: we know how bright a Type Ia supernova should be, so we can tell how far away it must be from how dim it appears. One uncertainty in this method is that intergalactic dust in between Earth and a supernova blocks some of its light. How do you know how much of the reduction in light is caused by distance, and how much by dust? With the help of Hubble, there’s a clever workaround: take images of the same Type Ia supernovae in ultraviolet light, which is almost completely blocked by dust, and in infrared light, which passes through dust almost unaffected. By carefully noting how much light comes through at each wavelength, the relationship between supernova brightness and distance can be calibrated to account for dust. Hubble can observe both these wavelengths of light in great detail with the same instrument. That makes it the perfect tool for this experiment, and indeed, some of the data used to make this beautiful image of NGC 3810 were focused on its 2022 supernova. You can see it as a point of light just below the galactic nucleus, or in the annotated image here.

There are many ways to measure cosmic distances; because Type Ia supernovae are so bright, they are one of the most useful and accurate tools, when they’re spotted. Many other methods must be used as well, either as an independent check against other distance measurements or to measure at much closer or farther distances. One such method that also works for galaxies is comparing their rotation speed to their brightness; based on that method, NGC 3810 is found to be 50 million light-years from Earth.

[Image Description: A spiral galaxy seen almost face-on. Large spiral arms whirl out from its centre, filling the scene. They glow faintly blue from the stars within, with some small bright patches of blue and pink marking areas of star formation. They are overlaid with thin filaments of dark reddish dust that block light. The galaxy’s centre shines brightly white.]

Found among the rich starfields of the Milky Way, star cluster NGC 7789 lies about 8,000 light-years away toward the constellation Cassiopeia. A late 18th century deep sky discovery of astronomer Caroline Lucretia Herschel, the cluster is also known as Caroline’s Rose. Its visual appearance in small telescopes, created by the cluster’s complex of stars and voids, is suggestive of nested rose petals. Now estimated to be 1.6 billion years young, the galactic or open cluster of stars also shows its age. All the stars in the cluster were likely born at the same time, but the brighter and more massive ones have more rapidly exhausted the hydrogen fuel in their cores. These have evolved from main sequence stars like the Sun into the many red giant stars shown with a yellowish cast in this color composite. Using measured color and brightness, astronomers can model the mass and hence the age of the cluster stars just starting to “turn off” the main sequence and become red giants. Over 50 light-years across, Caroline’s Rose spans about half a degree (the angular size of the Moon) near the center of the sharp telescopic image.

Sir Richard Starkey MBE (born 7 July 1940), known professionally as Ringo Starr, is an English musician, songwriter and actor who achieved international fame as the drummer for the Beatles. Starr occasionally sang lead vocals with the group, usually for one song on each album, including “Yellow Submarine” and “With a Little Help from My Friends“. He also wrote and sang the Beatles songs “Don’t Pass Me By” and “Octopus’s Garden“, and is credited as a co-writer of four others.

Starr was afflicted by life-threatening illnesses during childhood, with periods of prolonged hospitalisation. As a teenager Starr became interested in the UK skiffle craze and developed a fervent admiration for the genre. In 1957, he co-founded his first band, the Eddie Clayton Skiffle Group, which earned several prestigious local bookings before the fad succumbed to American rock and roll around early 1958. When the Beatles formed in 1960, Starr was a member of another Liverpool group, Rory Storm and the Hurricanes. After achieving moderate success in the UK and Hamburg, he quit the Hurricanes when he was asked to join the Beatles in August 1962, replacing Pete Best.

In addition to the Beatles’ films, Starr has acted in numerous others. After the Beatles disbanded, he released several successful singles including the US top-ten hit “It Don’t Come Easy“, and number ones “Photograph” and “You’re Sixteen“. His most successful UK single was “Back Off Boogaloo“, which peaked at number two. He achieved commercial and critical success with his 1973 album Ringo, which was a top-ten release in both the UK and the US. Starr has also featured in numerous documentaries, hosted television shows, narrated the first two series of the children’s television programme Thomas & Friends and portrayed “Mr. Conductor” during the first season of the PBS children’s television series Shining Time Station. Since 1989, he has toured with thirteen variations of Ringo Starr & His All-Starr Band.

Starr’s playing style, which emphasised feel over technical virtuosity, influenced many drummers to reconsider their playing from a compositional perspective. He also influenced various modern drumming techniques, such as the matched grip, tuning the drums lower, and using muffling devices on tonal rings. In his opinion, his finest recorded performance was on the Beatles’ “Rain“. In 1999, he was inducted into the Modern Drummer Hall of Fame. In 2011, Rolling Stone readers named him the fifth-greatest drummer of all time. He was inducted twice into the Rock and Roll Hall of Fame, as a Beatle in 1988 and as a solo artist in 2015, and appointed a Knight Bachelor in the 2018 New Year Honours for services to music.

“Time is always moving on; nothing can stop it. We can’t change the past, but we can shape the future. The more compassionate you are, the more you will find inner peace. From my own limited experience I have found that the greatest degree of inner tranquility comes from the development of love and compassion.” Dali Lama

Spiral galaxy M83 lies a mere twelve million light-years away, near the southeastern tip of the very long constellation Hydra. About 40,000 light-years across, M83 is known as the Southern Pinwheel for its pronounced spiral arms. But the wealth of reddish star forming regions found near the edges of the arms’ thick dust lanes, also suggest another popular moniker for M83, the Thousand-Ruby Galaxy. This new deep telescopic digital image also records the bright galaxy’s faint, extended halo. Arcing toward the bottom of the cosmic frame lies a stellar tidal stream, debris drawn from massive M83 by the gravitational disruption of a smaller, merging satellite galaxy. Astronomers David Malin and Brian Hadley found the elusive star stream in the mid 1990s by enhancing photographic plates.