A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.
A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.
Opinion
Astronomy has turned to a new chapter with the first images relayed from the James Webb Space Telescope (JWST) released this week.
The faintest features in the first “deep-field” image, published in yesterday's paper, departed about 13.7 billion years ago — around 0.1 billion years after the universe began itsexpansion from an initial state of high density and temperature with the Big Bang. It included a cluster of comparatively nearby galaxies, the gravity of which acts to bend and concentrate light from far, far more distant ones behind them. The faintest of those “gravitationally-lensed” galaxies are the most distant objects humans have ever seen in infrared light.
The JWST was launched on Christmas Day 2021 and began deploying its parts two weeks later, 1 million kilometres from Earth. Callibration then began as the telescope was manoevred towards Lagrange 2, a point in space about 1.5km from Earth where the gravitational fields of Earth and the Sun create a “gravity well”; the telescope orbits this point, where illumination from both the Sun and Earth can be blocked by a single shield. With less fuel used in this process than expected, an initial goal of a 10-year life has been doubled, with Nasa believing it can keep the JWST in place for 20 years.
So starts a search of the cosmos with a more advanced “eye”, able to capture three crucial types of images much more effectively than the Hubble telescope — launched in 1990 and still operating — can: the old, the cold (including newly-forming planets) and the dusty (where JWST will allow humans to view for the first time nurseries of young stars, and clouds of matter falling into black holes).
The JWST should help humanity answer some of the big remaining questions about the make-up and early formation of the universe.
Speaking of big, here is a pointer to the scale of the universe:
Our galaxy, the Milky Way, is estimated to have 100-400 billion stars and at least that number of planets. Our Sun is an average-sized star (some are 100 times larger). It has a circumference of 4.37 million km (109x bigger than the Earth).
For further mind-boggling context, Hubble has revealed an estimated 100 billion galaxies in the universe. It is expected that this will increase to about 200 billion with better telescope technology in space. It has been estimated there are about 200 billion trillion stars in the universe, and 20 sextillion planets (that's 2 plus 22 zeros).
