Category Archives: Asteroids

2016 CG18 Coming Tomorrow


2016 CG18 is a newly discovered asteroid and it will pass very close to us tomorrow (06 Feb), just 0.39 Lunar Distance or 149,916 km / 93,153 miles away.  The closest point will occur at 13:29 UTC.

149,000 to 150,000 km is really close in cosmological terms fortunately there isn’t any worries about 2016 CG18 getting any closer for a while.  Orbital calculations shown at ESA’s  NEODys-2 site show this is the closest approach until at least the year 2100.

The most remarkable thing about the asteroid is that it is only 7 meters across and the Catalina Sky Survey was able to find it on 03 February — that’s really good!

Image: JPL / NASA hat tip to Ron Baalke

UPDATE:  Just learned of another asteroid called 2015 NJ3, this is termed as a “Potentially Hazardous Asteroid”, NOT that is is a danger anytime soon that we know of but one that bears watching.  Preliminary data is just out, more to come.

Christmas Eve Visitor

2003 SD220 is a large asteroid that passed by Earth on 24 December 2015.  This image from  NASA’s 230-foot (70-meter) Deep Space Network antenna at Goldstone, California on 22 December 2015.


The 2.4 km / 1.5 mile long asteroid passed just 11 million km / 6.8 million miles which is pretty close in astronomic terms.  It will pass even closer in 2018 when it will be just 2.8 million km / 1.8 million miles away.


This second radar image was taken on 17 December 2015 when the asteroid was 12 million km / 7.3 million miles away.


Image: NASA/JPL-Caltech/GSSR


Asteroid to Make a Close Encounter

Radar images are improving as this video of 1998 WT24 shows.  Only 400 meters across and 4.3 million km / 2.7 million miles away, this is great resolution.

We have a VERY close encounter coming up today.  At 12:07 today Asteroid 2105 YB is going to pass just 0.2 LD from the Earth.  Thats only 76,880 km / 47,770 miles, very close indeed.  Note there is some uncertainty of the time of closest passage, it’s possibly up to 1.7 hours off.  2105 YB is 10 meters in diameter and was only discovered a few days ago so the number of observations are limited so far and as you can imagine these things are terrifically hard to see.

More observations will improve the accuracy of predicted future positions.  2105 YB might make a good choice for a radar target as any asteroid this close could (not saying it does) pose a potential risk.



Halloween Asteroid Update


This updated set of images of the Halloween asteroid released yesterday.  Very nice detail for radar images.  Be sure to click the image above for a larger version.

Asteroid 2015 TB145 is depicted in eight individual radar images collected on Oct. 31, 2015 between 5:55 a.m. PDT (8:55 a.m. EDT) and 6:08 a.m. PDT (9:08 a.m. EDT). At the time the radar images were taken, the asteroid was between 440,000 miles (710,000 kilometers) and about 430,000 miles (690,000 kilometers) distant. Asteroid 2015 TB145 safely flew past Earth on Oct. 31, at 10:00 a.m. PDT (1 p.m. EDT) at about 1.3 lunar distances (300,000 miles, 480,000 kilometers).

To obtain the radar images, the scientists used the 230-foot (70-meter) DSS-14 antenna at Goldstone, California, to transmit high power microwaves toward the asteroid . The signal bounced of the asteroid, and their radar echoes  were received by the National Radio Astronomy Observatory’s 100-meter (330-foot) Green Bank Telescope in West Virginia. The images achieve a spatial resolution of about 13 feet (4 meters) per pixel.

Image Credit: NASA/JPL-Caltech/GSSR/NRAO/AUI/NSF

Pushing Asteroids

A rotating asteroid heats up in the sunlight side and as the warmed area rotates into the dark and cold, the stored heat is radiated away. The heat radiated into the cold can cause thrust and push on an asteroid.

The amount of “push” wouldn’t be much, yet over time it can add up and cause the asteroid to change their paths. If you have followed the talk about how to divert a potentially dangerous asteroid you will know variations of this theme has come up.

Asteroid With a Moon

Asteroid 2004 BL86 made a relatively close pass yesterday. The asteroid passed about 3.1 lunar distances from Earth or 1.2 million km / 745,000 miles. In cosmic scales that is indeed close. The asteroid is 325 meters / 1,100 feet in diameter, not something we would want to hit us!

Scientists used the Deep Space Network antenna at Goldstone California took took radar images of the asteroid and assembled 20 of them into this video and look at what they found – the asteroid has a moon! Actually about 16 percent of the near-Earth population of asteroids of 200 meters in diameter (655 feet) have moons and a few have two. This particular moon is 70 meters (230 feet) across.

The observations of the asteroid enabled scientists to get data on the orbit to predict future close passes and this asteroid will not make another pass this close for 200 years. We do have others though, the next known asteroid to make a close pass is called 1999 AN10 in 2027.

The asteroid was found on Jan. 30, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico, one of a handful of observing groups around the world looking for these very difficult to find objects.

Video source

Ceres Here We Come

The dwarf planet Ceres from 1.2 million km / 740,000 miles Image: Dawn Spacecraft/NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The dwarf planet Ceres from 1.2 million km / 740,000 miles Image: Dawn Spacecraft/NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Yet another space mission soon to bring new discovery is Dawn.

Dawn launched in 2007 and provided stunning views and scientific data on the protoplanet Vesta. Dawn spent 14 months orbiting Vesta before leaving for the dwarf planet Ceres.

Vesta and Ceres are two of the larger bodies in the asteroid belt that lies between Mars and Jupiter and Ceres is the larger of the two. There are thousands of asteroids in the belt, however when we see the asteroid belt in the movies we always see the spaceships having to weave their way through a maze of rocks. It isn’t even close to being accurate the distribution is such that on average the distance between asteroids is about twice the Earth to Moon distance.

There was speculation the asteroid belt was created by pieces of planet that either never formed or broke apart. We know this isn’t the case, more than likely the belt is “left-over” bits. It is estimated that if all the asteroids were put together to make one body, that body would only be around 1500 km in diameter.

There is much knowledge to be gained by the Ceres visit. Dawn will be making the approach phase to Ceres on 26 December when the speed and trajectory will be tweaked so the spacecraft will be captured by Ceres’ gravitational field in March 2015.

What are the largest asteroids? Here are the top 11. Yes I made a top 11 so I could include 3 Juno.

The number before the name is the discovery sequence and has nothing to do with size. You can get the particulars at our Asteroids page.

1 Ceres
2 Pallas
4 Vesta
10 Hygiea
704 Interamnia
52 Europa
511 Davida
87 Sylvia
65 Cybele
15 Eunomia
3 Juno

Bollide Map

Bolide map 1994 - 2013.  Image credit: Planetary Science via NASA
Bolide map 1994 – 2013. Image credit: Planetary Science via NASA

Here’s a great map especially if you like fireballs as much as I do. As you will read below it is a map of small asteroid strikes. I find the distribution of daytime/nighttime remarkable. Sure it’s about 50/50 as you would expect but I’d think the daytime ones would be more difficult to detect – apparently not.

Check out the links at the end of the article.

From NASA’s Near Earth Object (NEO) Program:

A map released today by NASA’s Near Earth Object (NEO) Program reveals that small asteroids frequently enter and disintegrate in the Earth’s atmosphere with random distribution around the globe. Released to the scientific community, the map visualizes data gathered by U.S. government sensors from 1994 to 2013. The data indicate that Earth’s atmosphere was impacted by small asteroids, resulting in a bolide (or fireball), on 556 separate occasions in a 20-year period. Almost all asteroids of this size disintegrate in the atmosphere and are usually harmless. The notable exception was the Chelyabinsk event which was the largest asteroid to hit Earth in this period. The new data could help scientists better refine estimates of the distribution of the sizes of NEOs including larger ones that could pose a danger to Earth.


Finding and characterizing hazardous asteroids to protect our home planet is a high priority for NASA. It is one of the reasons NASA has increased by a factor of 10 investments in asteroid detection, characterization and mitigation activities over the last five years. In addition, NASA has aggressively developed strategies and plans with its partners in the U.S. and abroad to detect, track and characterize NEOs. These activities also will help identify NEOs that might pose a risk of Earth impact, and further help inform developing options for planetary defense.


The public can help participate in the hunt for potentially hazardous Near Earth Objects through the Asteroid Grand Challenge, which aims to create a plan to find all asteroid threats to human populations and know what to do about them. NASA is also pursuing an Asteroid Redirect Mission (ARM) which will identify, redirect and send astronauts to explore an asteroid. Among its many exploration goals, the mission could demonstrate basic planetary defense techniques for asteroid deflection.


For more information about the map and data, go to:

For details about ARM, and the Asteroid Grand Challenge, visit:

2014 UF56

A newly discovered 11-meter wide asteroid passed by Earth at about 164,244 km/ 102,056 miles or 0.43 LD (lunar distance) at 21:20 on 27 Oct 2014.

JPL Small-Body Database.

The asteroid discovery credit goes to a Mt. Lemmon Survey observation at 0521 UT 25 Oct. 2014

This asteroid will come back around in 2018 but shouldn’t be anywhere near as close according to NEODys.