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Could This Asteroid Hit Earth? Astronomers Go “Back in Time” to Find the Answer

Potentially hazardous asteroid 2016 WJ1 was discovered in Oct. 2016—but also in July 2003. Credit: Canada-France-Hawaii Telescope

Astronomers are always watching the skies for observations of near-Earth asteroids—”space rocks” that have orbits close to Earth’s and, in the case of potentially hazardous asteroids (aka PHAs), those whose orbits could actually cross Earth’s and are larger than 150 meters (500 ft) across. When a new one of these is discovered—no small feat considering that many are very dark, move quickly, and could really be anywhere in the sky—it’s a scramble to determine the object’s orbital parameters and figure out just how close it can get to us and when. Such was the case on Oct. 19, 2016, when the asteroid 2016 WJ1 was identified with the Catalina Sky Survey. This object, estimated to be anywhere from 110 to 340 meters across—easily within the potentially hazardous range—was initially calculated to pose a threat in 2065 with a possible impact risk, albeit a very small one. Eventually though, scientists were able to refine the risk chance with more observations of 2016 WJ1…observations that had actually occurred over 13 years earlier.

Read the full story from ESA here: Asteroid sleuths go back to the future

This is Earth and the Moon Seen From Mars

The Moon and Earth imaged from Mars. Credit: NASA/JPL-Caltech/University of Arizona

The Moon and Earth imaged from Mars. Credit: NASA/JPL-Caltech/University of Arizona

Here’s a view of our home planet and its lovely Moon captured from 127 million miles away by NASA’s Mars Reconnaissance Orbiter on November 20, 2016. The sunlit part of Earth shows eastern Asia, the Indian Ocean, and Australia with ice-covered Antarctica visible as a bright white spot. The Moon has been brightened in this image, since it would be too dark in relation to a properly-exposed Earth to be readily visible (and I added more dark background to frame them a bit better.) But the positions and sizes of the two worlds are as captured by the HiRISE instrument, which was designed to map the surface of Mars in exquisite detail but occasionally is aimed to take a look back homeward.

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The Scale of the Solar System With a Soccer Ball, a Drone, Pin Heads, and Planet Nine

I love models that demonstrate the incredible size and space of the Solar System, very much so because many illustrations and diagrams fail to portray it accurately (and for very good reason…it’s enormous.) The most recent is shown here, enthusiastically created and narrated by former NASA engineer Mark Rober. This particular demonstration is unique in that it’s the only one (that I’ve seen so far) that includes the newest possible-planet in the Solar System, “Planet Nine,” a Neptune-mass world that may orbit the Sun up to four times farther away than Pluto. Check it out above, and you can find some other cool scale models of the Solar System I’ve encountered previously below.

(And remember kids, space is really, really, really BIG.)

How Big is the Solar System?
What is Space?
If the Moon Were Only 1 Pixel
A Matter of Scale
A Scale Model of the Solar System Like You’ve Never Seen Before

Europe’s Sentinel-3A Returns Gorgeous “First Light” Earth Images

Day to night transition over Norway captured by ESA's Sentinel 3A satellite. Credit: Copernicus data (2016).

Day to night transition over Norway captured by ESA’s Sentinel 3A satellite. Credit: Copernicus data (2016).

Captured by the EU’s Copernicus Sentinel-3A satellite on Feb. 29, 2016, this beautiful composition of blacks, purples, and blues shows the twilight transition across the Norwegian archipelago of Svalbard, located north of the Arctic Circle between Norway and the North Pole.  The snow-covered and fjord-cut large island of Spitsbergen can be seen at the right edge, while sea ice and clouds follow their own swirling currents on and above the Greenland sea.

This is the first image acquired by the spacecraft, which was launched aboard a converted-ICBM Rockot vehicle on Feb. 16 from Russia’s Plesetsk Cosmodrome. The first of two planned Sentinel-3 satellites, 3A is currently in a high-inclination orbit at an altitude of 505 miles (814 km).

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Pale Blue Dot: Our Valentine from Voyager 1

If you’re in love with space exploration then you’ll fall for this: a picture of Earth (and five other planets) taken from the Voyager 1 spacecraft after it passed the orbit of Pluto in 1990, 26 years ago today. That image of our planet from almost 4 billion miles away inspired Carl Sagan to write his famous “Pale Blue Dot” passage, and reminds us that we are all just floating on “a mote of dust suspended in a sunbeam.”

This is from a post I originally published in 2010. I’ll keep trotting it out until it’s not cool anymore. (Which I don’t think will ever will NEVER happen.)

Venus, Earth, Jupiter, Saturn, Uranus and Neptune as seen by Voyager 1 in 1990 (Credit: NASA)

On February 14, 1990, after nearly 13 years of traveling the solar system, the Voyager 1 spacecraft passed the orbit of Pluto and turned its camera around to take a series of photos of the planets. The image above shows those photos, isolated from the original series and are left to right, top to bottom: Venus, Earth, Jupiter, Saturn, Uranus, and Neptune.

From that distance, over 4 billion miles from the Sun, the planets each appear as little more than a bright dot against the vastness of interplanetary space.

“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”

– Carl Sagan

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Is This New Picture of Earth From the Moon for Real? Yes, Yes It Is.

An "Earthrise" over Compton crater as imaged by LRO on Oct. 12, 2015. Credit: NASA/GSFC/Arizona State University

An “Earthrise” over Compton crater as imaged by LRO on Oct. 12, 2015. Credit: NASA/GSFC/Arizona State University

Today NASA released an amazing image of Earth taken from the Moon — specifically from lunar orbit by NASA’s Lunar Reconnaissance Orbiter, which has been studying our Moon since the summer of 2009. In it our planet appears as an incredibly bright blue globe with swashes of white clouds and Africa and northeastern South America clearly visible beyond the rolling grey hills of the Moon. It’s so clear and perfect it almost doesn’t look real — so is it?

Why yes. Yes it is. (But of course there was a little help needed from the LROC imaging teams at Arizona State University and Goddard Space Flight Center!)

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