Watch Asteroid 2016 VA Pass Through Earth’s Shadow

Article written: 2 Nov , 2016
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Holy low-flying space rocks, Batman.

Newly discovered asteroid 2016 VA snuck up on us last night, and crossed through the Earth’s shadow to boot.

Discovered just yesterday by the Mount Lemmon Sky Survey based outside of Tucson Arizona, 2016 VA passed just 58,600 miles (93,700 kilometers) from the surface of the Earth this morning at 00:42 Universal Time (UT). That’s a little over 20% of the distance from the Earth to the Moon, and just over twice the distance to the ring of geosynchronous and geostationary satellites around the Earth.

This sort of close pass of a newly discovered asteroid happens a few times a year. What made 2016 VA’s passage unusual, however, was its transit through the Earth’s shadow. The discovery was announced yesterday by the Minor Planet Center, and astronomer Gianluca Masi soon realized that the Virtual Telescope Project had a unique opportunity to capture the asteroid on closest approach.

The passage of asteroid 2016 VA. Image credit: The Virtual Telescope Project.

Asteroid 2016 VA. Image credit: The Virtual Telescope Project.

Gianluca Masi explained how the difficult capture was done:

“The image is a 60-second exposure, remotely taken with “Elena” (a PlaneWave 17” +Paramount ME+SBIG STL-6303E robotic unit) available at the Virtual Telescope project. The robotic mount tracked the extremely fast apparent motion of the asteroid, so stars are trailing. The asteroid is perfectly tracked; it is the sharp dot in the center, marked with two white segments. At imaging time, asteroid 2016 VA was at about 200,000 kilometers from us and approaching.”

Catching a fast-moving asteroid such as 2016 VA on closest approach isn’t easy. First off, there’s an amount of uncertainty surrounding the orbit of a newly discovered object until more observations can be made. 2016 VA passed close enough to the Earth that our planet’s gravity substantially altered the tiny asteroid’s future orbit. Also, a house-sized Earth-crosser like 2016 VA is really truckin’ across the sky on closest approach: 2016 VA was moving at 1500” a minute through Earth’s shadow – that’s 25” a second, fast enough to cross the apparent diameter of a Full Moon in just 72 seconds.

Masi also notes:

“During its flyby, asteroid 2016 VA was also eclipsed by the Earth. We covered the spectacular event, clearly capturing the penumbral effects. The movie is an amazing document showing the eclipse. Each frame comes from a 5-second integration.”

Watch as 2016 VA winks out as it hits Earth's shadow... Image credit: The Virtual Telescope Project.

Watch as 2016 VA winks out as it hits Earth’s shadow… Image credit: The Virtual Telescope Project.

At an estimated 16 to 19 meters in size, 2016 VA shined at 13th magnitude as it crossed the southern hemisphere constellation of Sculptor on closest approach. It crossed through the Earth’s shadow for 11 minutes from 23:23 to 23:34 UT last night, just over an hour before closest approach. You can see the dimming effect of the Earth’s outer penumbral shadow in the video,  just before the asteroid strikes the inner dark umbra and emerges back into eternal sunshine once again. Sitting on 2016 VA, and observer would have seen a total solar eclipse, as the bulk of the Earth passed between the asteroid and the Sun in an event not witnessed by the tiny world for thousands of years.

Such transits of asteroid through the Earth’s shadow have been observed before: 2012 XE54 crossed through the Earth’s shadow a few years back, and 2008 TC3 crossed through the Earth’s shadow before striking the Nubian desert in the early morning hours of October 7th, 2008.

Satellites in geostationary orbit also pull a similar vanishing act right around either equinox as well.

The orbit of 2016 VA. Iimage credit: NASA/JPL.

The orbit of 2016 VA. Image credit: NASA/JPL.

2016 VA is also a similar size to another famous space rock: the 20 metre asteroid that exploded over the city of Chelyabinsk the day after Valentine’s Day in 2013. 2016 VA gave us a miss, and won’t make another pass as close to the Earth again for this century.

To our knowledge, such a video capture of an asteroid crossing through Earth’s shadow is a first, or at least the first that we’ve seen circulated on ye ole Web.

The light curve of 2016 as it passed through the Earth's shadow. Image credit: Peter Birtwhistle, Great Shefford Observatory.

The light curve of 2016 as it passed through the Earth’s shadow. Image credit: Peter Birtwhistle, Great Shefford Observatory.

Congrats to the good folks at the Virtual Telescope Project for swinging into action so quickly, and providing us with an amazing view!

-Catch the closest Full Moon of the year (and for many years to come!) on November 14th live courtesy of the Virtual Telescope Project.

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4 Responses

  1. ronfurg says

    This is fascinating. Kudos to the folks doing the super telescopic work.

  2. ProfMOZ says

    Asteroid Warning System
    NICE, but where was the 5-day advance notice? 😉

    • Spikey says

      The 5-day advance notice was not possible because the target was not visible because of daylight until less than 24 hours to closest approach. I hope this extract from the Horizons Web Interface (ssd.jpl.nasa.gov/horizons.cgi) makes that clear:
      Target body name: (2016 VA)
      Center body name: Earth (399)
      Center-site name: GEOCENTRIC
      Date__(UT)__HR:MN R.A._(J2000.0)_DEC. S-O-T /r
      2016-Oct-28 00:42 60.81487 56.78834 131.2645 /L
      2016-Oct-29 00:42 60.71970 56.69170 132.0081 /L
      2016-Oct-30 00:42 60.52368 56.50280 132.8506 /L
      2016-Oct-31 00:42 60.09543 56.09142 133.9413 /L
      2016-Nov-01 00:42 58.81325 54.80330 136.0257 /L
      2016-Nov-02 00:42 25.33592 -28.77329 134.9487 /T
      Column meaning:
      S-O-T /r =
      Sun-Observer-Target angle; target’s apparent SOLAR ELONGATION seen from
      the observer location at print-time. Angular units: DEGREES
      The ‘/r’ column indicates the target’s apparent position relative to
      the Sun in the observer’s sky, as described below:
      For an observing location on the surface of a rotating body (considering its rotational sense):
      /T indicates target TRAILS Sun (evening sky; rises and sets AFTER Sun)
      /L indicates target LEADS Sun (morning sky; rises and sets BEFORE Sun)

  3. While I was doing research into the mythological connection to the Younger Dryas Impact Hypothesis and reading the cuneiform text The Seven Tables of the History of Creation I thought of what this article is about. “O Marduk, thou art our avenger ! We give thee sovereignty over the Whole World. Thy Weapon shall never lose its power, it shall Crush thy foe O Lord, Spare the Life of him that putteth his Trust in thee, but as for the God who began the rebellion, pour out its Life. Command that the cloak disappear ! Then command that the cloak return ! Marduk proceeds to the test. As he gave command, the cloak disappeared. He spoke again and the cloak was there. Now go against Tiamat, cut off her life, let the winds carry her blood to hidden regions.”
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