Archive for the ‘space’ Tag
A sense of universal perspective
Leave a CommentThe Hubble Space Telescope (HST) has once again been peering into the dark depths of space and has delivered us another spectacular image of the farthest reaches of the observable universe1. This image was taken using a recently installed wide field camera, which detects light in the near infra-red portion of the light spectrum, just beyond the red part of the spectrum and which is invisible to human eyes.
HST Ultra deep field image (click for larger view)
The space telescope stared intently at a tiny spot in the sky, which to the naked eye and even most telescopes would appear dark and empty. Over the course of 4 days of looking at that one spot, the individual photons of light exposed an image of hundreds of galaxies in the outermost regions of space.
If this image doesn’t blow you away, then perhaps you just need a little perspective. You might want to take a seat first. In Douglas Adams’ The Hitchhiker’s Guide to the Galaxy the process of achieving a sense of perspective in the universe was the most tortuous thing any sentient being could undergo and a machine was invented to do just that. It was called the Total Perspective Vortex and it gave its victims a true perspective of their place in the universe, which amounted to a “microscopic dot on a microscopic dot”.
I promise not to fry your brains, as the Total Perspective Vortex did, but will instead attempt to open your eyes to the awesome size of the universe. Let me start by describing what a galaxy is, by describing our own: the Milky Way. It is comprised of a few hundred billion stars, much like our own sun and a great many of which have planets orbiting them too. These are the stars we see when we go outside on a dark, cloudless night and look up at the sky.
To appreciate the size of the Milky Way galaxy, we measure it in terms of the time it would take a light beam to travel from one side to the other. In the vacuum of space, light travels at 300 000 km every second, yet it would still take 100 000 years to traverse the galaxy.
Now look again at that picture from Hubble. It contains hundreds of galaxies. And that is just a view of a tiny speck of sky. As far as we know, looking beyond the stars of our own galaxy, every other speck of sky would show the exact same thing: galaxies extending in all directions as far as we can see. And if we could look beyond all those galaxies in the picture, we would likely see more and more galaxies. Because the universe is expanding, the light from all the galaxies will never reach us, no matter how long we stare, but it is obvious that the little we can see is far from little.
If you still can’t wrap your head around what you’re seeing and want to try another perspective, watch the following video from the American Museum of Natural History. It starts with a view of planet Earth and proceeds to zoom out until the view encompasses all the known and observable universe. Hold on to your hats for a wild ride.
When it appears that those around you are busy staring at their proverbial navels, investing their time in the celebrity gossip pages or concerning themselves with how many angels could dance on the head of a pin, it is refreshing to stand back and appreciate the true magnificence of the wider universe in which we live. You may think the universe is something out there and far too distant and abstract to be regarded a part of our daily lives, but thanks to the incredible science and engineering that gave us tools like the HST, we are now able to visualise it, measure it and come to understand it. The universe is here and we are a part of it, and it is more incredible than anything our imaginations might conceive.
Notes and references:
1) Hubble’s Deepest View of Universe Unveils Never-Before-Seen Galaxies
2) Thanks to gfish for bringing this video to my attention.
Lunar deep freeze holds water
Now that the dust has settled, both metaphorically and literally, the scientists at NASA have managed to take a careful look at the masses of data gathered by the LCROSS mission to the moon and are already reporting great success1.
Lunar craters 2
The mission went according to plan, crashing a spent rocket booster into a crater of the moon on the 9th of October, while instruments aboard the shepherding spacecraft viewed the event and the resulting plume of ejected material.
This “bombing” of the moon, as some media sources liked to call it, was eagerly anticipated by the inhabitants of Earth, who were expecting to see something spectacular. Nothing about this kind of science is guaranteed and the enormous spray of gas, dust and debris did not materialise, much to the disappointment of those watching through telescopes, or at the live images broadcast on TV and over the Internet.
The reports that came out over the following hours and days sounded like a collective “blah” as the public turned its back on space science with a dismissive wave of the hand. Many journalists, talking heads and commentators, unimpressed with the lack of “fireworks”, questioned the value of such interplanetary ventures. Science doesn’t always give instant gratification and those criticisms were premature. After a careful examination of the data, some preliminary results are now in, and they are far more interesting than any puff of gas.
The cloud of debris kicked up by the rocket impact actually reached several kilometres above the lunar surface, exposing long frozen material from within the permanently shadowed depths of the target crater. Spectrometers aboard LCROSS recorded the presence of the constituent elements in the ejected material, as they were lit up by the sun for the first time in a few billion years. From these data, NASA scientists have already concluded that there were “significant” quantities of water ice present there.
The availability of water on the moon would be a big asset for future colonies there, providing not only drinking water but also oxygen to breathe and fuel to power the habitat. These lunar deep freezers may also contain other interesting elements which might hold clues to the formation of our solar system. Again, the scientific methods requires a little more patience from us, while the data from this valuable and intellectually profitable mission continue to be analysed.
References:
1) LCROSS Impact Data Indicates Water on Moon
2) Image courtesy of NASA (far side of the moon photographed from Apollo 11 in lunar orbit).
Back to the moon with some hard hitting science
Lift off for LRO and LCROSS (Courtesy NASA)
Like any curious boy or girl wanting to understand how something works and what it’s made of, the tried and tested method that always seems to deliver results is brute force; hitting something hard and cracking the curiosity open to reveal what’s inside. The engineers and scientists at NASA are no exception when it comes to using this primeval method and they’re heading back to the moon with something that packs an astronomical punch.
This afternoon, NASA launched the Lunar reconnaissance Orbiter (LRO), along with the Lunar Crater Observation and Sensing Satellite (LCROSS), aboard an Atlas V rocket from Cape Canaveral in Florida.
The LRO will begin its mission next week, orbiting the moon and imaging its surface in great detail, providing valuable data for the selection of future landing sites and perhaps even a manned moon base.
The job of LCROSS, in October of this year, is to smash its way into the moon’s surface. First it will separate from the Centaur rocket to which it is attached and watch as it crashes into the lunar pole, where scientists suspect water might be found. Instruments on board LCROSS will analyse the ejected material as it passes through the plumes sent up from the impact, shortly before the spacecraft itself crashes into the planet and meets its end.
The ejected material from both impacts will be illuminated by the sun and will also be studied by Earth and space based telescopes, including LRO. If we’re lucky, they may glimpse evidence of water on our otherwise rocky neighbour, a much needed resource for a moon base or any other human colony.
