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| The Rho Ophiuchi region. Credits: NASA, ESA, CSA, STScI, Klaus Pontoppidan (STScI) |
It is a relatively small, quiet stellar nursery, but you’d never know it from Webb’s chaotic close-up. Jets bursting from young stars crisscross the image, impacting the surrounding interstellar gas and lighting up molecular hydrogen, shown in red. Some stars display the telltale shadow of a circumstellar disk, the makings of future planetary systems.
The young stars at the centre of many of these discs are similar in mass to the Sun or smaller. The heftiest in this image is the star S1, which appears amid a glowing cave it is carving out with its stellar winds in the lower half of the image. The lighter-coloured gas surrounding S1 consists of polycyclic aromatic hydrocarbons, a family of carbon-based molecules that are among the most common compounds found in space.
The Rho Ophiuchi cloud complex is approximately 390 light years from Earth, which is peanuts when compared to the vastness of space, though it would still take 14,500,000 years of travel to get there using current technology. For more big numbers see later the calculations covering stars and galaxies in the universe.
Webb’s image shows a region containing approximately 50 young stars, all of them similar in mass to the Sun, or smaller. The darkest areas are the densest, where thick dust cocoons still-forming stars. The huge bipolar jets of molecular hydrogen occur when a star first bursts through its natal envelope of cosmic dust, shooting out a pair of opposing jets into space like a newborn first stretching her arms out into the world. In contrast, the star S1 has carved out a glowing cave of dust in the lower half of the image. It is the only star in the image that is significantly more massive than the Sun.
A Webb image
from last month is that of part of the NGC 5068 galaxy.
The pinhead dots of light from a myriad of stars in the NGC 5068 galaxy
How many stars are there in the universe? The answer is an absolutely astounding number. There are approximately 200 billion trillion stars in the universe. Or, to put it another way, 200 sextillion. That's 200,000,000,000,000,000,000,000! (Source: Astronomy.com)
Ethan Siegel in Forbes explored another instance of massive numbers. He states that in the estimates of how many galaxies there are in the observable universe there is a huge discrepancy between the lower limit of 176 billion derived by a Hubble eXtreme Deep Field image of a limited area and the estimates produced by simulations for the observable universe based on these three components:
The remarkable answer? With the state of scientific knowledge we have at present, two trillion galaxies should exist within our observable universe, Siegel writes. Two trillion versus 176 billion means that more than 90% of the galaxies within our universe are beyond the detection capabilities of even what has been humanity's greatest observatory. We shall have to wait to see what the Webb craft can teach us of the splendours of the universe.the ingredients that make up the Universe,
the right initial conditions that reflect our reality,
and the correct laws of physics that describe nature.
One thing more from NASA for the number-crunchers:
Our Sun is one of at least 100 billion stars in the Milky Way, a spiral galaxy about 100,000 light-years across. The stars are arranged in a pinwheel pattern with four major arms, and we live in one of them, about two-thirds of the way outward from the center.
Most of the stars in our galaxy are thought to host their own families of planets.
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