This image from the NASA/ESA Hubble Space Telescope captures the spiral galaxy NGC 105, which lies ... [+] roughly 215 million light-years away in the constellation Pisces. While it looks like NGC 105 is plunging edge-on into a collision with a neighbouring galaxy, this is just the result of the chance alignment of the two objects in the night sky. NGC 105’s elongated neighbour is actually far more distant and remains relatively unknown to astronomers. These misleading conjunctions occur frequently in astronomy — for example, the stars in constellations are at vastly different distances from Earth, and only appear to form patterns thanks to the chance alignment of their component stars. The Wide Field Camera 3 observations in this image are from a vast collection of Hubble measurements examining nearby galaxies which contain two fascinating astronomical phenomena — Cepheid variables and cataclysmic supernova explosions. Whilst these two phenomena may appear to be unrelated — one is a peculiar class of pulsating stars and the other is the explosion caused by the catastrophic final throes of a massive star’s life — they are both used by astronomers for a very particular purpose: measuring the vast distances to astronomical objects. Both Cepheids and supernovae have very predictable luminosities, meaning that astronomers can tell precisely how bright they are. By measuring how bright they appear when observed from Earth, these “standard candles” can provide reliable distance measurements. NGC 105 contains both supernovae and Cepheid variables, giving astronomers a valuable opportunity to calibrate the two distance measurement techniques against one another. Astronomers recently carefully analysed the distances to a sample of galaxies including NGC 105 to measure how fast the Universe is expanding — a value known as the Hubble constant. Their results don’t agree with the predictions of the most widely-accepted cosmological model, and their analysis shows tha
ESA/Hubble & NASA, D. Jones, A.
If you thought the Hubble Space Telescope was about to be surpassed by the new James Webb Space Telescope (Webb) , think again.
Now on its way to its observing position a million miles from Earth, Webb has a 6.6 meter mirror—compared to the 2.4-meter mirror inside Hubble—so six times more collecting power.
Should we compare Webb with Hubble? No—Webb is an infrared telescope while Hubble deals mainly in optical (visible) light.
Besides, Hubble has just issued a stunning new image, one of several in the last few weeks, that prove that there’s plenty of life left in the old space telescope yet.
Forbes In Photos: See The Dramatic Final Images Of NASA's $10 Billion Webb Space Telescope After Its Christmas Day Launch By Jamie Carter
The main image of this article, above, was released yesterday and shows a spiral galaxy called NGC 105 about 215 million light-years away in the constellation Pisces. It also shows, top-left, a smaller galaxy. Are the two colliding? No—it’s merely a chance alignment of the two objects in the night sky. That smaller galaxy is much further away.
The lonely spiral galaxy UGC 9391 is shown in this image from the NASA/ESA Hubble Space Telescope’s ... [+] Wide Field Camera 3. This galaxy resides 130 million light-years from Earth in the constellation Draco near the north celestial pole. The star-studded spiral arms stand in splendid isolation against a backdrop of distant galaxies, which are only visible as indistinct swirls or smudges thanks to their vast distances from Earth. The image also features some much brighter foreground stars closer to home. These bright nearby stars are ringed with diffraction spikes — prominent spikes caused by light interacting with the inner workings of Hubble’s complicated optics. This image is from a set of Hubble observations which astronomers used to construct the “Cosmic Distance Ladder” — a set of connected measurements allowing the distances to the most distant astronomical objects to be determined. Astronomical distances are only directly measurable for relatively nearby objects — closer than 3000 light-years or so. For distances beyond this, astronomers rely on a set of measured correlations calibrated against nearby objects. UGC 9391 helped astronomers improve their distance estimates by providing a natural laboratory in which to compare two measuring techniques — supernova explosions and Cepheid variables. Improving the precision of distance measurements helps astronomers quantify how quickly the Universe is expanding — one of Hubble’s key science goals.
ESA/Hubble & NASA, A. Riess et a
Released a few weeks ago is this image (above) of another, lonelier spiral galaxy called UGC 9391. About 130 million light-years from Earth in the constellation of Draco, the Dragon, in the northern sky, you can see myriad distant galaxies behind it, between the swirls.
The open star cluster NGC 1755 resembles a pinch of salt strewn on a jet-black tablecloth in this ... [+] image from the NASA/ESA Hubble Space Telescope. This collection of stars resides in one the Milky Way’s near neighbours — the Large Magellanic Cloud — and measures 120 light-years from side to side. Despite this impressive breadth, NGC 1755 is a member of the smaller class of star clusters. Star clusters are gravitationally bound collections of stars, and come in two main varieties — smaller open clusters like NGC 1755, which are hosts to younger stars, and gargantuan globular clusters, which can contain millions of older stars. Hubble gazed into the heart of NGC 1755 in order to better understand how different populations of stars can co-exist in a single cluster. A population of stars is a group of stars with similar properties such as age or chemical composition, and these populations provide astronomers with valuable insights into the births, lives, and deaths of stars. Clusters in the Magellanic Clouds are particularly useful natural laboratories thanks to the Clouds’ proximity to the Milky Way. Hubbles’s eagle-eyed vision was a vital asset when observing NGC 1755 — with so many stars packed into a small area of sky, Hubble’s high-resolution Advanced Camera for Surveys and Wide Field Camera 3 allowed individual stars in the cluster to be distinguished.
ESA/Hubble & NASA, A. Milone, G.
Here’s the open star cluster NGC 1755 is an image published during December 2021. About 120 light-years from side to side, NGC 1755 isn’t actually within our galaxy, but one orbiting it—the incredible Large Magellanic Cloud (LMC), a satellite galaxy. Easy to see right now from the southern hemisphere, the LMC is one of those little-known cosmic objects that you simply must see once in your lifetime.
In this image, the NASA/ESA Hubble Space Telescope captures a side-on view of NGC 3568, a barred ... [+] spiral galaxy roughly 57 million light-years from the Milky Way in the constellation Centaurus. In 2014 the light from a supernova explosion in NGC 3568 reached Earth — a sudden flare of light caused by the titanic explosion accompanying the death of a massive star. Whilst most astronomical discoveries are the work of teams of professional astronomers, this supernova was discovered by amateur astronomers from the Backyard Observatory Supernova Search in New Zealand. Dedicated amateur astronomers often make intriguing discoveries — particularly of fleeting astronomical phenomena such as supernovae. This Hubble observation comes from a hoard of data built up to pave the way for future science with the upcoming NASA/ESA/CSA James Webb Space Telescope. By combining ground-based observations with data from Hubble’s Advanced Camera for Surveys and Wide Field Camera 3, astronomers have built a treasure trove of data on the connections between young stars and the clouds of cold gas in which they form. One of Webb’s key science goals is to explore the life cycle of stars — particularly how and where stars are born. Since Webb observes at infrared wavelengths, it will be able to peer through the clouds of gas and dust in stellar nurseries and observe the fledgling stars within. Webb’s superb sensitivity will even allow astronomers to directly investigate faint protostellar cores — the earliest stages of star birth.
ESA/Hubble & NASA, M. Sun
Another December 2021 image, above, shows a side-on view of NGC 3568, a barred spiral galaxy about 57 million light-years from the Milky Way in the constellation of Centaurus. The image is the result of preparatory data collected to help Webb investigate where stars are born.
The image combines data from Hubble with ground-based telescopes that specifically focuses on the connections between young stars and the clouds of cold gas in which they form. Webb’s infrared skills will allow it to look through the clouds of gas and dust you can see here.
This stellar whirlpool is a spiral galaxy named NCG 7329, which has been imaged by Hubble’s Wide ... [+] Field Camera 3 (WFC3). Creating a colourful image such as this one using a telescope such as Hubble is not as straightforward as pointing and clicking a camera. Commercial cameras will typically try to collect as much light of all visible wavelengths as they can, in order to create the most vibrant images possible. In contrast, raw images collected by Hubble are always monochromatic, because astronomers typically want to capture very specific ranges of wavelengths of light at any time, in order to do the best, most accurate science possible. In order to control which wavelengths of light will be collected, Hubble’s cameras are equipped with a wide variety of filters, which only allow certain wavelengths of light to reach the cameras’ CCDs (a CCD is a camera’s light sensor — phone cameras also have CCDs!). How are the colourful Hubble images possible given that the raw Hubble images are monochromatic? This is accomplished by combining multiple different observations of the same object, obtained using different filters. This image, for example, was processed from Hubble observations made using four different filters, each of which spans a different region of the light spectrum, from the ultraviolet to optical and infrared. Specialised image processors and artists can make informed judgements about which optical colours best correspond to each filter used. They can then colour the images taken using that filter accordingly. Finally, the images taken with different filters are stacked together, and voila! The colourful image of a distant galaxy is complete, with colours as representative of reality as possible.
ESA/Hubble & NASA, A. Riess et a
The final December 2021 image from Hubble is of spiral galaxy NCG 7329, but it’s not as naturally colorful as it seems. Hubble takes images only in black and white and the final image we see here is produced by combining multiple different observations using four different filters.
This image was processed from Hubble observations made using four different filters that span the light spectrum, from the ultraviolet to visible and near-infrared. Which color is used for each filter is down to specialised image processors and artists before the final image is stacked.
Wishing you clear skies and wide eyes.