It sounds like an almost unbelievable: Anders Helstrup went skydiving nearly two years ago in Hedmark, Norway and while he didn’t realize it at the time, when he reviewed the footage taken by two cameras fixed to his helmet during the dive, he saw a rock plummet past him. He took it to experts and they realized he had captured a meteorite falling during its “dark flight” — when it has been slowed by atmospheric braking, and has cooled and is no longer luminous.
Posts Tagged ‘Astronomy’
The Galaxy and Mass Assembly catalogue is a detailed map of the Universe showing where galaxies are in 3D. This simulated flythrough shows the real positions and images of the galaxies that have been mapped so far. Distances are to scale, but the galaxy images have been enlarged for your viewing pleasure.
Remember each little speck is an entire galaxy, not just a single star. Our Solar System’s star, the Sun, is merely one of the 100–400 billion stars in our galaxy The Milky Way.
Get ready to see an awful lot of galaxies …
A monster version of our sun has been found, the largest known member of the family of yellow stars to which our sun belongs.
The whopper sun emits light in similar wavelengths as our sun but its diameter is over 1300 times larger. That means it would engulf all the planets between Mercury and Jupiter if placed at the centre of our solar system. The star’s size also means it is touching its smaller, companion star (see diagram, below).
Dubbed HR 5171 A, the star is located in the constellation Centaurus around 12,000 light years from Earth.
The two stars orbit each other, forming a binary system. However, though their centres are separated by more than the distance between our sun and Saturn, HR 5171 A is so large that the two are touching, forming a continuous peanut-shaped structure. Guess this star system ain’t big enough for two. Learn more here.
NASA has announced a torrent of new planet discoveries, hailing a “bonanza” of 715 worlds now known outside the solar system thanks to the Kepler space telescope’s planet-hunting mission.
A new method for verifying potential planets led to the volume of new discoveries from Kepler, which aims to help humans search for other worlds that may be like Earth.
The 715 newly verified planets are orbiting 305 different stars.
The latest announcement brings the number of known planets to between 1500 and 1800, depending on which of the five main extra-solar planet-discovery catalogues is used. Learn more here.
Sometimes when you reach for the stars, the stars reach back. This cloud of gas and dust has been nicknamed the Hand of God, due to its eerie shape. The cloud is made of material that a star ejected when it exploded and is now being sculpted by the stellar core that remained.
More great images here.
A spacecraft drive-by has provided new footage of something we all take for granted – the orbit of the moon around Earth.
NASA’s Juno spacecraft has flown past our planet on its way to Jupiter, and managed to catch footage of the Moon as it performed an eternal tango with its hefty blue partner.
Juno used a gravitational slingshot manoeuvre to accelerate itself into the solar system after it was launched towards the asteroid belt in early August.
It received a boost in speed of more than 14,000 kph (about 7.3 kilometres per second), which set it on course for a July 4, 2016, rendezvous with Jupiter.
The spacecraft is equipped with an array of advanced sensors, including a special camera optimised for tracking faint stars, it was this camera that was trained towards Earth as the ship shot by, resulting in an intriguing, low-resolution glimpse of what we would look like to a visitor from afar.
Learn more here.
On a dark night, far from the Equator, you might be lucky enough to spot an aurora: a shimmering, colourful glow in the sky. This natural light show has captivated people for thousands of years. While it is mostly associated with cold, dark nights near the poles, auroras have a much brighter, warmer origin: the Sun.
The extremely high temperatures of the solar surface produce plasma. Plasma isn’t a gas, solid or liquid. It’s a fourth state of matter, made up of charged particles also known as ions. The stream of plasma that shoots outwards from the Sun is called the solar wind.
The solar wind travels in all directions, and Earth is constantly being bombarded by fast-moving ions from the Sun. Earth has a magnetic field, so when the solar wind hits Earth, the charged particles are attracted to Earth’s magnetic poles.
As the ions move through Earth’s atmosphere, they collide with molecules of gas, such as oxygen and nitrogen. These collisions transfer energy from the ions to the gas molecules. The molecules are now in an excited state. To come back down to their unexcited state, the gas molecules release energy in the form of coloured light. This can be seen from Earth’s surface as an aurora.
The amount of solar activity varies. Sometimes there isn’t much solar wind, and an aurora isn’t visible. Peaks of solar activity occur roughly every 11 years, and it’s been about that long since the last one. Recently some large solar flares were detected on the Sun’s surface. This evidence suggests a solar maximum is approaching, which could result in brighter and more wide-spread auroras.
It is difficult to predict when an aurora will appear, and even when one does, it can move and disappear in an instant. Science can explain many aspects of auroras. However, their elusive and unpredictable nature combined with their beauty means they still seem somewhat magical. Learn more here, here or here.
To most people, exploration means the kinds of things that travelers did in the past — Captain James Cook charting islands in the vast Pacific Ocean or Robert Peary and Frederick Cook planting a flag at the North Pole. The 1960s and ’70s Apollo landings, with their flags and footprints legacy, were a continuation of this idea and many people assume that this is how future planetary exploration will proceed.
This probably won’t be so …
With ever-improving computing power and communication protocols, astronauts could float in a space station in orbit around the moon or Mars, donning exoskeleton controllers to teleoperate robots in real time. These probes would drive, fly, drill, dig, scoop, and gather material faster and with more precision than current probes controlled from Earth. The best part of humans, our powerful brains that can identify the perfect geologic rock sample and make decisions on the fly, would be combined with all the advantages of robots — their advanced cameras, suites of instruments, and bodies that aren’t prone to degenerative problems like blindness and bone loss after months of space travel. One day our mechanical proxies could even help humans visit places that would destroy our bodies, like the hellish surface of Venus or the frozen ocean of Europa. Learn more here.
Lightning storms on Saturn and Jupiter could create carbon soot that might be compressed into diamonds as it falls through the atmosphere.
Scientists theorise that lightning zaps molecules of methane in the upper atmospheres of Saturn and Jupiter, liberating carbon atoms. These atoms then stick onto each other, forming larger particles of carbon soot (which the Cassini spacecraft may have spotted in dark storm clouds on Saturn). As the soot particles slowly float down through ever-denser layers of gaseous and liquid hydrogen towards the planets’ rocky cores, they experience ever greater pressures and temperatures. The soot is compressed into graphite, and then into solid diamonds before reaching a temperature of about 8,000 °C, when the diamond melts, forming liquid diamond raindrops.
Inside Saturn, the conditions are right for diamond ‘hail’ to form, beginning at a depth of about 6,000 kilometres into the atmosphere and extending for another 30,000 km below that. If you had a robot there, it would sit there and collect diamonds raining down. Learn more here.
Astronomers have created the first map of the clouds on a planet outside our Solar System.
The planet in question is Kepler-7b, a large gaseous world like Jupiter, roughly 1,000 light-years away.
The researchers used data from Nasa’s Spitzer and Kepler space telescopes to study the exoplanet, which orbits close to its parent star.
Their results suggest the hot giant is marked by high clouds in the west and clear skies in the east.
Astronomers have previously been able to make temperature maps of planets orbiting other stars, but this is the first look at cloud structures on a distant world. Kepler-7b is something of an oddity – bigger than Jupiter, but lower in mass – with a density about the same as polystyrene. Learn more here, here or here.