Andromeda (M31) e Triangolo (M33), le due galassie giganti più vicine alla nostra Via Lattea. Queste, insieme ad una trentina di più "piccole" fanno parte del Gruppo Locale (si stima che il suo diametro sia di 4 milioni di anni luce!)
I computer non sono stati sempre fatti di schede madri e CPU. Un tempo, erano umani! E al Jet Propulsion Laboratory della NASA, i computer umani erano una squadra di donne talentuose, diventate le prime programmatrici di computer. In questa foto del 1959, un computer umano lavora con un computer-macchina, presto chiamato IBM 704. Questi ultimi erano in grado di fare alcuni calcoli veloci, ma non erano ancora affidabili o efficienti come gli esseri umani.
Crediti: NASA / JPL-Caltech
happy 127 bday Mr. Hubble 💕🔭
On the occasion of astronomer Edwin Hubble’s birthday, let’s take a look at his stock in trade – galaxies. It was through his observations of these celestial wonders that Hubble changed our perception of the universe. This excerpt from NASA’s bio will give you the gist (and please note that all these galactic images are, of course, captured by the Hubble Space Telescope):
“Most astronomers of Hubble’s day thought that all of the universe — the planets, the stars seen with the naked eye and with powerful telescopes, and fuzzy objects called nebulae — was contained within the Milky Way galaxy. Our galaxy, it was thought, was synonymous with the universe.
In 1923 Hubble trained the Hooker telescope on a hazy patch of sky called the Andromeda Nebula. He found that it contained stars just like the ones in our galaxy, only dimmer. One star he saw was a Cepheid variable, a type of star with a known, varying brightness that can be used to measure distances. From this Hubble deduced that the Andromeda Nebula was not a nearby star cluster but rather an entire other galaxy, now called the Andromeda galaxy.
In the following years he made similar discoveries with other nebulae. By the end of the 1920s, most astronomers were convinced that our Milky Way galaxy was but one of millions in the universe. This was a shift in thought as profound as understanding the world was round and that it revolved around the sun.
Hubble then went one step further. By the end of that decade he had discovered enough galaxies to compare to each other. He created a system for classifying galaxies into ellipticals, spirals and barred spirals — a system called the Hubble tuning fork diagram, used today in an evolved form.
But the most astonishing discovery Hubble made resulted from his study of the spectra of 46 galaxies, and in particular of the Doppler velocities of those galaxies relative to our own Milky Way galaxy. What Hubble found was that the farther apart galaxies are from each other, the faster they move away from each other. Based on this observation, Hubble concluded that the universe expands uniformly. Several scientists had also posed this theory based on Einstein’s General Relativity, but Hubble’s data, published in 1929, helped convince the scientific community.”
You can click photos to identify the galaxies.
(Text: NASA/Images: HubbleSite)
It’s Friday, Sept. 15 and our Cassini mission has officially come to a spectacular end. The final signal from the spacecraft was received here on Earth at 7:55 a.m. EDT after a fateful plunge into Saturn’s atmosphere.
After losing contact with Earth, the spacecraft burned up like a meteor, becoming part of the planet itself.
Although bittersweet, Cassini’s triumphant end is the culmination of a nearly 20-year mission that overflowed with discoveries.
Mission Team and Data
Now that the spacecraft is gone, most of the team’s engineers are migrating to other planetary missions, where they will continue to contribute to the work we’re doing to explore our solar system and beyond.
Mission scientists will keep working for the coming years to ensure that we fully understand all of the data acquired during the mission’s Grand Finale. They will carefully calibrate and study all of this data so that it can be entered into the Planetary Data System. From there, it will be accessible to future scientists for years to come.
Even beyond that, the science data will continue to be worked on for decades, possibly more, depending on the research grants that are acquired.
Other team members, some who have spent most of their career working on the Cassini mission, will use this as an opportunity to retire.
Future Missions
In revealing that Enceladus has essentially all the ingredients needed for life, the mission energized a pivot to the exploration of “ocean worlds” that has been sweeping planetary science over the past couple of decades.
Jupiter’s moon Europa has been a prime target for future exploration, and many lessons during Cassini’s mission are being applied in planning our Europa Clipper mission, planned for launch in the 2020s.
The mission will orbit the giant planet, Jupiter, using gravitational assists from large moons to maneuver the spacecraft into repeated close encounters, much as Cassini has used the gravity of Titan to continually shape the spacecraft’s course.
In addition, many engineers and scientists from Cassini are serving on the new Europa Clipper mission and helping to shape its science investigations. For example, several members of the Cassini Ion and Neutral Mass Spectrometer team are developing an extremely sensitive, next-generation version of their instrument for flight on Europa Clipper. What Cassini has learned about flying through the plume of material spraying from Enceladus will be invaluable to Europa Clipper, should plume activity be confirmed on Europa.
In the decades following Cassini, scientists hope to return to the Saturn system to follow up on the mission’s many discoveries. Mission concepts under consideration include robotic explorers to drift on the methane seas of Titan and fly through the Enceladus plume to collect and analyze samples for signs of biology.
Atmospheric probes to all four of the outer planets have long been a priority for the science community, and the most recent recommendations from a group of planetary scientists shows interest in sending such a mission to Saturn. By directly sampling Saturn’s upper atmosphere during its last orbits and final plunge, Cassini is laying the groundwork for an potential Saturn atmospheric probe.
A variety of potential mission concepts are discussed in a recently completed study — including orbiters, flybys and probes that would dive into Uranus’ atmosphere to study its composition. Future missions to the ice giants might explore those worlds using an approach similar to Cassini’s mission.
Learn more about the Cassini mission and its Grand Finale HERE.
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Ricostruzione 3D dalla superficie del pianeta Trappist-1D. Gli altri sei pianeti sono vicini e tutti ben visibili all'orizzonte. https://m.youtube.com/watch?v=o2MgG6KhO1E&version=3&rel=0&autoplay=1
Ieri Margaret Hamilton ha ricevuto il prestigioso premio "Presidential medal of freedom" per aver guidato con successo il team per la creazione dell'on-board computer dell'Apollo 11, permettendo quindi il primo allunaggio umano della storia
We don’t have any real pictures of the Milky Way galaxy. Most non-illustrated images of the entire Milky Way spiral are actually of another spiral galaxy called Messier 74. It’s impossible to take a full photo of the Milky Way’s spiral structure because it’s about 100,000 light-years across, and we’re stuck on the inside. Source Source 2 Source 3
This is about as good as we can get:
This picture of the Milky Way was captured by NASA’s COBE satellite. This photograph was taken using the infrared spectrum, which allows astronomers to peer through the gas and dust that normally obscures the center of the Milky Way.
Image Credit: The COBE Project, DIRBE, NASA
celestial bodies
Christianus Prolianus, Astronomia, Naples 1478
Manchester, John Rylands University Library, Latin MS 53, fol. 58v
“Dear God, please don’t let me fuck up.”
—Alan Shepard