Mercury is the innermost planet in the solar system, only 58 million kilometres to the Sun. It’s only slightly larger than our Moon and just as rocky, with extensive plains, heavy cratering, mountains, highlands and valleys. Its atmosphere is thin and any geologic activity the planet once experienced is now extinct, so impacts from comets and asteroids are preserved exquisitely. Mercurcy’s thin atmosphere also means that it has trouble retaining heat, so temperatures fluctuate hugely: up to 430 degrees C on the surface during the day and as low as -180 degrees C at night.
Mercury is one of the least understood planets in the solar system. Only two spacecraft have ever been sent there. Mariner 10 visited in 1974-75, and MESSENGER was launched in 2004 and is still orbit, continually learning about this small but violent planet. The images above are from these missions. Click the images for captions.
Over the past 25 years, Hubble has made more than 1.2 million observations and generated a staggering 100 terabytes of data. Narrowing down my favorite image is nearly impossible but I’ve managed to highlight a few.
The Eagle Nebula I’m not sure Hubble has produced a more majestic image than this one of the Eagle Nebula. This image shows the famous “Pillars of Creation” and the nebula’s multi-colored glow of gas clouds, wispy tendrils of dark cosmic dust, and the rust-colored elephants’ trunks of the nebula’s famous pillars. The dust and gas in the pillars is seared by the intense radiation from young stars and eroded by strong winds from massive nearby stars.
Hubble Ultra Deep Field Peering back to nearly the beginning of time, this image shakes me at my core and illustrates the unimaginable vastness of the cosmos. This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Called the Hubble Ultra Deep Field, this galaxy-studded view represents a "deep” core sample of the universe, cutting across billions of light-years. The snapshot includes galaxies of various ages, sizes, shapes, and colors. The smallest, reddest galaxies, about 100, may be among the most distant known, existing when the universe was just 800 million years old.
The Antennae The galaxies — also known as NGC 4038 and NGC 4039 — are locked in a deadly embrace. Once spiral galaxies similar to our own Milky Way, the pair have spent the past few hundred million years sparring with one another. This clash is so violent that stars have been ripped from their host galaxies to form a streaming arc between the two. Clouds of gas are seen in bright pink and red, surrounding the bright flashes of blue star-forming regions — some of which are partially obscured by dark patches of dust. The rate of star formation is so high that the Antennae Galaxies are said to be in a state of starburst, a period in which all of the gas within the galaxies is being used to form stars. This is a preview of what might happen when our Milky Way galaxy collides with the approaching Andromeda galaxy in a few billion years.
The Tarantula Nebula About 170,000 light-years away, is a turbulent star-forming region in the Large Magellanic Cloud called the Tarantula Nebula. It is close to Earth that Hubble can make out individual stars. It is home to many extreme conditions including supernova remnants and the heaviest star ever found, R136a1. The Tarantula Nebula is the most luminous nebula of its type in the local Universe as a result of the raucous stellar breeding ground located at its heart known as 30 Doradus.
Helix Nebula The Helix Nebula, located 690 light-years from Earth, is a ball of glowing gas expelled from a dying sun-like star. This image is a composite of a photograph taken by Hubble in 2002 and one by a telescope in Chile in 2003. The object is so large that both telescopes were needed to capture a complete view. It resembles a simple doughnut as seen from Earth but new evidence suggests that the Helix consists of two gaseous disks nearly perpendicular to each other.
Happy birthday, Hubble! The celebrated space telescope turns 25 on Friday. To mark the anniversary, NASA set the instrument loose to gaze at some fireworks – that is, space fireworks. Hubble captured the spectacular photos of stars being born in “Westerlund 2,” a cluster of 3,000 stars that is in Gum 29, which NASA describes as a “raucous stellar breeding ground” in the constellation Carina.
John Martinaeu - The Dance of Venus (An accurate scientific drawing of Venus stunning pattern around the Earth. Our closest planetary neighbour draws a huge pentagram pattern around Earth every 8 years or 13 Venusian years. Four of the eight-year Venus cycles are shown, with the motion of Venus around Earth over 32 years), “A Little Book of Coincidence”, 2002.
How We Know How Many Galaxies There Are In The Universe, Thanks To Hubble
“This latter image, consisting of a region of space barely a thousandth of a square degree on the sky – so small it would take thirty-two-million of them to fill the entire sky — contains a whopping 5,500 galaxies, the most distant of which have had their light traveling towards us for some 13 billion years, or more than 90% the present age of the Universe. Extrapolating this over the entire sky, we find that there are 170 billion galaxies in the observable Universe, and that’s just a lower limit.”
In 1996, astronomers conducted an experiment with the Hubble telescope which was deemed risky at the time. They pointed the orbiting space telescope toward the constellation of the Big Dipper (Ursa Major). The patch of sky Hubble was directed to observe was no bigger than a grain of sand held out at arm’s length from an observer. Over 10 consecutive days, Hubble collected photons from an area seemingly devoid of anything interesting. For all we knew, the images returned could’ve been as dark and empty as it appeared from our terrestrial vantage point.
However, the device we were using to collect this 13.8 billion-year-distant light was humanity’s most sophisticated window to the universe. And when the lens was closed and the images were processed, history - literally and figuratively - was well, not made, but – rediscovered. Every single pixel of light that fell onto Hubble’s detector were the celestial fingerprints of 3,000+ galaxies, each galaxy containing hundreds of billions of stars.
So, in 2004, the experiment was performed again - this time, toward the constellation Orion - for 11 days and 400 complete orbits around the Earth. The upgraded detectors allowed even more photons to be captured than ever before, revealing to us again, the immensity of the undeniably expanding universe.
As if the Hubble Space Telescope couldn’t have personified our human curiosity ever greater, NASA measured the redshifts of all the galaxies in the 1996 “Hubble Deep Field” image and applied them to a 3D model. You can experience this cosmic journey through time (and space) HERE.
Curiosity-driven approaches to scientific research embody what it means to be human, embolden us to take risks, and encourage us to fearlessly confront the unknown. In an attempt to simply peer beyond our limited cosmic horizon, our inquisitiveness about the universe created a device capable of reaching into a perceived patch of “nothing” and revealed how quaint of a position our planet and our species occupy in the cosmos.
At Endeavorist, these are the types of paradigm-shifting discoveries we’re dedicated to enabling through the democratization of #freescience.