The second known asteroid discovered orbiting closer to the Sun than Venus
Using ground-based telescopes scanning the morning and evening sky, an astronomer has discovered only the second known asteroid circling the Sun within the orbit of Venus.
The manner of the discovery itself, by Scott Sheppard of the Carnegie Institution, also illustrated our modern world.
He first observed it using the Cerro Tololo Dark Energy Camera the night before leaving on a hiking trip. Because the object was moving fast, he knew it must be very close to the Sun, so he’d need to image it again and soon to confirm its orbit before it became lost in the Sun’s glare.
“I had to schedule new observations to re-observe the object while deep in the forest of Pennsylvania,” he says. “It is just amazing that even camp sites today have good Wi-Fi access — that allowed me to download the new second observations of this asteroid and determine its unique orbit that is interior to Venus.”
Astronomers have found so few asteroids close to the Sun because the Sun’s glare makes observations difficult. Some scientists like to speculate to the press that there could be a large unknown population, with some posing a threat to Earth. The computer predictions however say the population is small, because the push of the Sun’s light and radiation should easily shift their orbits outward or make them unstable.
The two asteroids so far found confirm these models in a counter-intuitive way. The new asteroid is estimated to be a little less than a half mile across, while the previously discovered asteroid is thought to have a diameter of more than a mile. Their larger size makes it harder for the Sun’s light and radiation to shift their orbit.
In other words, this inner population of asteroids is likely to be low in number, but made up of larger objects.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Using ground-based telescopes scanning the morning and evening sky, an astronomer has discovered only the second known asteroid circling the Sun within the orbit of Venus.
The manner of the discovery itself, by Scott Sheppard of the Carnegie Institution, also illustrated our modern world.
He first observed it using the Cerro Tololo Dark Energy Camera the night before leaving on a hiking trip. Because the object was moving fast, he knew it must be very close to the Sun, so he’d need to image it again and soon to confirm its orbit before it became lost in the Sun’s glare.
“I had to schedule new observations to re-observe the object while deep in the forest of Pennsylvania,” he says. “It is just amazing that even camp sites today have good Wi-Fi access — that allowed me to download the new second observations of this asteroid and determine its unique orbit that is interior to Venus.”
Astronomers have found so few asteroids close to the Sun because the Sun’s glare makes observations difficult. Some scientists like to speculate to the press that there could be a large unknown population, with some posing a threat to Earth. The computer predictions however say the population is small, because the push of the Sun’s light and radiation should easily shift their orbits outward or make them unstable.
The two asteroids so far found confirm these models in a counter-intuitive way. The new asteroid is estimated to be a little less than a half mile across, while the previously discovered asteroid is thought to have a diameter of more than a mile. Their larger size makes it harder for the Sun’s light and radiation to shift their orbit.
In other words, this inner population of asteroids is likely to be low in number, but made up of larger objects.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Good news and bad news here. Good news is that we found one, as they are hard to detect (looking into the sun). The bad news is that there are more of them (same reason as before). Cheers –
Speaking of which:
https://phys.org/news/2025-10-hidden-sun-glare-asteroid-uncomfortably.html
A scientist at the Carnegie Institute for Science has discovered a new asteroid in our neighborhood. Its name is 2025 SC79 and it’s the newest member of the Atira asteroid group. These are near-Earth asteroids with orbits entirely within Earth’s orbit. Atiras are the least numerous group of near-Earth objects and 2025 SC79 is the 39th member.
These objects are challenging to spot because their meager light is drowned out by the sun’s overpowering glare. This new space rock is only the second known object with an orbit entirely within Venus’ orbit. It also crosses Mercury’s orbit, and completes a trip around the sun in only 128 days. It has the third shortest orbital period of any asteroid, with the two fastest ones both having an orbital period of only 115 days. For comparison, Mercury’s orbital period is only 88 days.
Carnegie Science astronomer Scott S. Sheppard discovered the asteroid on September 27 with the Dark Energy Camera on the National Science Foundation’s Blanco 4-meter telescope. That telescope searches for killer asteroids, and 2025 SC79 certainly qualifies. 2025 SC79 is about 700 meters (2,300 ft) in diameter. While small compared to the Chicxulub impactor that ended the dinosaurs, that size asteroid would still create a catastrophic impact on a continental scale. Depending on where it landed, it could kill billions of people and animals.
We really need a satellite on the dark side of mercury looking out. Right now we would never see it coming.
David K,
There is no dark side of Mercury. But putting three equally-spaced instruments on Mercury would ensure continuous ability to use its bulk as a sunscreen when making observations so your general idea is a good one.
Asteroid defense papers
https://www.secretprojects.co.uk/threads/260-srm-as-an-icbm.12990/page-2#post-680471