“As the large parent body of the Geminids, asteroid 3200 Phaethon, continues on its tight orbit around the Sun, it will continue to expel matter and be torn apart, bit by tiny bit. The asteroid is about the size of the one that struck Earth 65 million years ago, causing our last great mass extinction. But instead of colliding with us all at once, this ~6 km wide asteroid is slowly dissipating in the presence of the Sun, creating tails of matter and ions but also an ever-thickening debris stream.
With each mid-December that rolls past, Earth slams through that debris stream, creating a show that gets progressively more spectacular with each set of orbits that regularly tick by. Over the past 15 years, the Geminids have regularly been one of the two best displays of meteor showers on Earth, and it’s eminently possible that 2020 will set a new record. The Moon, the Earth, and all of the other predictable conditions are just right for a spectacular show. If the clouds cooperate on December 13 and 14, treat yourself to the greatest natural show of the year. With all that 2020 has brought us, we can all use a cosmic treat like this one.”
Can everyone just have a good thing to enjoy? Can we all just have something nice that we don’t have to fight over? Well, nature might deliver what humanity has been unable to bring us for 2020: a natural show that can’t be stopped by anything, except for clouds.
Get your Geminid fix today, and then look up on December 13/14 to fully enjoy the show!
The Kepler space telescope has taught us there are so many planets out there, they outnumber even the stars. Here is a sample of these wondrous, weird and unexpected worlds (and other spectacular objects in space) that Kepler has spotted with its “eye” opened to the heavens.
Yes, Star Wars fans, the double sunset on Tatooine could really exist. Kepler discovered the first known planet around a double-star system, though Kepler-16b is probably a gas giant without a solid surface.
Nope. Kepler hasn’t found Earth 2.0, and that wasn’t the job it set out to do. But in its survey of hundreds of thousands of stars, Kepler found planets near in size to Earth orbiting at a distance where liquid water could pool on the surface. One of them, Kepler-62f, is about 40 percent bigger than Earth and is likely rocky. Is there life on any of them? We still have a lot more to learn.
One of Kepler’s early discoveries was the small, scorched world of Kepler-10b. With a year that lasts less than an Earth day and density high enough to imply it’s probably made of iron and rock, this “lava world” gave us the first solid evidence of a rocky planet outside our solar system.
When Kepler detected the oddly fluctuating light from “Tabby’s Star,” the internet lit up with speculation of an alien megastructure. Astronomers have concluded it’s probably an orbiting dust cloud.
What happens when a solar system dies? Kepler discovered a white dwarf, the compact corpse of a star in the process of vaporizing a planet.
The five small planets in Kepler-444 were born 11 billion years ago when our galaxy was in its youth. Imagine what these ancient planets look like after all that time?
This premier planet hunter has also been watching stars explode. Kepler recorded a sped-up version of a supernova called a “fast-evolving luminescent transit” that reached its peak brightness at breakneck speed. It was caused by a star spewing out a dense shell of gas that lit up when hit with the shockwave from the blast.
* All images are artist illustrations.
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The galaxy is perfect
“In Einstein’s initial formulation of General Relativity way back in 1916, he mentioned the gravitational redshift (and blueshift) of light as a necessary consequence of his new theory, and the third classical test, after the precession of Mercury’s perihelion (already known at the time) and the deflection of starlight by a gravitational source (discovered during a total solar eclipse in 1919).
Although a thought experiment is an extremely powerful tool, practical experiments didn’t catch up until 1959, where the Pound-Rebka experiment finally measured a gravitational redshift/blueshift directly. Yet just by invoking the idea that energy must be conserved, and a basic understanding of particle physics and gravitational fields, we can learn that light must change its frequency in a gravitational field.”
If a photon flies through space towards Earth, it must gain energy and become bluer in nature as it approaches Earth’s surface. This idea, of a gravitational redshift or blueshift, dictates how a photon must change in energy in the presence of a gravitational field. Yet this effect, which only exists in General Relativity, could have been predicted as soon as special relativity was discovered by one simple thought experiment: to consider a particle-antiparticle pair dropped from high above the surface of the Earth, but to let the annihilation occur at varying locations.
If you considered that, you’d immediately realize how special relativity was insufficient for describing our Universe! Come learn how to reason it out for yourself today!
Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is at its closest distance to Earth. 😍
These images, however, are more than just beauty shots. They reveal exquisite details of the planet as a part of the Outer Planets Atmospheres Legacy project to help scientists understand the atmospheric dynamics of our solar system’s gas giants.
This year’s Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Also, the mysterious six-sided pattern – called the “hexagon” – still exists on the north pole. Caused by a high-speed jet stream, the hexagon was first discovered in 1981 by our Voyager 1 spacecraft.
Saturn’s signature rings are still as stunning as ever. The image reveals that the ring system is tilted toward Earth, giving viewers a magnificent look at the bright, icy structure.
Image Credit: NASA, ESA, A. Simon (GSFC), M.H. Wong (University of California, Berkeley) and the OPAL Team
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Couple goals
This artist’s illustration shows the region around a supermassive black hole after a star wandered too close and was ripped apart by extreme gravitational forces. Some of the remains of the star are pulled into an X-ray-bright disk where they circle the black hole before passing over the “event horizon,” the boundary beyond which nothing, including light, can escape. The elongated spot depicts a bright region in the disk, which causes a regular variation in the X-ray brightness of the source, allowing the spin rate of the black hole to be estimated. The curved region in the upper left shows where light from the other side of the disk has been curved over the top of the black hole.
This event was first detected by a network of optical telescopes called the All-Sky Automated Survey for Supernovae (ASASSN) in November 2014. Astronomers dubbed the new source ASASSN14-li and traced the bright flash of light to a galaxy about 290 million light years from Earth. They also identified it as a “tidal disruption” event, where one cosmic object is shredded by another through gravity.
Astronomers then used other telescopes including a flotilla of high-energy telescopes in space — NASA’s Chandra X-ray Observatory, ESA’s XMM-Newton and NASA’s Neil Gehrels Swift observatory — to study the X-rays emitted as the remains of a star swirled toward the black hole at the center of the galaxy.
The tidal disruption in ASASSN-14li is intriguing because it allowed astronomers to measure the spin rate of the black hole. A black hole has two fundamental properties: mass and spin. While it has been relatively easy for astronomers to determine the mass of black holes, it has been much more difficult to get accurate measurements of their spins.
This debris from the shredded star gave astronomers an avenue to get a direct measure of the black hole’s spin in ASASSN-14li. They found that the event horizon around this black hole is about 300 times the diameter of the Earth, yet rotates once every two minutes (compared to the 24 hours it takes to complete one rotation). This means that the black hole is spinning at least half as fast as the speed of light.
Scientists have determined spin rates for some stellar-mass black holes (those that typically weigh between 5 and 30 solar masses) in our Milky Way galaxy by observing rapid and regular variations in their X-ray brightness. A few supermassive black holes have shown similar variations, but they were only observed to repeat over a few cycles, rather than the 300,000 cycles seen for ASASSN-14li. With only a few cycles, the association of the variations with the spin of the black hole is not secure.
These results will likely encourage astronomers to observe future tidal disruption events for long durations to look for similar, regular variations in their X-ray brightness. source
“The Milky Way’s gas, dust, stars and more create fascinating, measurable structures. Subtracting out all the foregrounds yields the cosmic background signal, which possesses tiny temperature imperfections. But the galactic foreground isn’t useless; it’s a map unto itself. All background light gets polarized by these foregrounds, enabling the reconstruction of our galaxy’s magnetic field.”
Have you ever wondered what our galaxy’s magnetic field looks like? As long as we restrict ourselves to looking in the type of light that human eyes can see, the optical portion of the spectrum, we’re extremely limited as far as what we can infer. However, if we move on to data from the microwave portion of the spectrum, and in particular we look at the data that comes from the polarization of background light (and the foreground light directly), we should be able to reconstruct our galaxy’s magnetic fields to the best precision ever. The Planck satellite, in addition to mapping the CMB to better precision than ever before, has enabled us to do exactly that.
Even though there are still some small questions and uncertainties, you won’t want to miss these incredible pictures that showcase just how far we’ve come!
“2.) We have extensive photographic and video evidence from the Apollo missions themselves. How could the lunar module have ascended back off of the surface and returned the astronauts back to the orbiting module which would take them back to Earth? Exactly like the video above shows, from direct Apollo 17 footage. The hypergolic propellant system isn’t based off of a single explosion, but rather a constant thrust of ~16,000 Newtons that was steadily delivered over a timespan of about 5 minutes. There’s no exhaust trail because there’s no lunar atmosphere, but you can track the spacecraft’s accelerated motion for yourself with even basic modern software.”
We’re less than a month away from the official 50th anniversary of the first crewed Moon landing, and there are all sorts of good reasons to celebrate. But for most of us alive today, the final Apollo mission occurred before we were born. Perhaps because of this distance between then and now, there are a great many people who don’t believe that the lunar landings ever occurred. While you might (rightfully) dismiss this position as an uninformed conspiracy, you can also immediately point to a slew of scientific evidence to demonstrate that yes, we did go to the Moon, and here is an enormous suite of data to back that up. From thousands of photographs to suites of instruments and scientific data to an examination of the landing sites today, everything lines up.
Come get the evidence for yourself, and don’t let someone’s conspiracy-minded ravings lead you astray.