PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Asteroids' close encounters with Mars

2013-11-19
(Press-News.org) Contact information: Sarah McDonnell
s_mcd@mit.edu
617-253-8923
Massachusetts Institute of Technology
Asteroids' close encounters with Mars CAMBRIDGE, MA -- For nearly as long as astronomers have been able to observe asteroids, a question has gone unanswered: Why do the surfaces of most asteroids appear redder than meteorites — the remnants of asteroids that have crashed to Earth?

In 2010, Richard Binzel, a professor of planetary sciences at MIT, identified a likely explanation: Asteroids orbiting in our solar system's main asteroid belt, situated between Mars and Jupiter, are exposed to cosmic radiation, changing the chemical nature of their surfaces and reddening them over time. By contrast, Binzel found that asteroids that venture out of the main belt and pass close to Earth feel the effects of Earth's gravity, causing "asteroid quakes" that shift surface grains, exposing fresh grains underneath. When these "refreshed" asteroids get too close to Earth, they break apart and fall to its surface as meteorites.

Since then, scientists have thought that close encounters with Earth play a key role in refreshing asteroids. But now Binzel and colleague Francesca DeMeo have found that Mars can also stir up asteroid surfaces, if in close enough contact. The team calculated the orbits of 60 refreshed asteroids, and found that 10 percent of these never cross Earth's orbit. Instead, these asteroids only come close to Mars, suggesting that the Red Planet can refresh the surfaces of these asteroids.

"We don't think Earth is the only major driver anymore, and it opens our minds to the possibility that there are other things happening in the solar system causing these asteroids to be refreshed," says DeMeo, who did much of the work as a postdoc in MIT's Department of Earth, Atmospheric and Planetary Sciences.

DeMeo and Binzel, along with former MIT research associate Matthew Lockhart, have published their findings in the journal Icarus.

Asteroid roulette

The idea that Mars may shake up the surface of an asteroid is a surprising one: As Binzel points out, the planet is one-third the size of Earth, and one-tenth as massive — and therefore exerts a far weaker gravitational pull on surrounding objects. But Mars' position in the solar system places the planet in close proximity with the asteroid belt, increasing the chance of close asteroid encounters.

"Mars is right next to the asteroid belt, and in a way it gets more opportunity than the Earth does to refresh asteroids," Binzel says. "So that may be a balancing factor."

DeMeo, who suspected that Mars may have a hand in altering asteroid surfaces, looked through an asteroid database created by the International Astronomical Union's Minor Planet Center. The database currently consists of observations of 300,000 asteroids and their orbits; 10,000 of these are considered near-Earth asteroids.

Over the past decade, Binzel's group has tracked the brightest of these asteroids, measuring their colors to determine which may have been refreshed recently. For this most recent paper, the researchers looked at 60 such asteroids, mapping out the orbit of each and determining which orbits had intersected with those of Earth or Mars. DeMeo then calculated the probability, over the last 500,000 years, that an asteroid and either planet would have intersected, creating a close encounter that could potentially generate asteroid quakes.

"Picture Mars and an asteroid going through an intersection, and sometimes they'll both come through at very nearly the same time," Binzel says. "If they just barely miss each other, that's close enough for Mars' gravity to tug on [the asteroid] and shake it up. It ends up being this random process as to how these things happen, and how often."

Refreshing the face of an asteroid

From their calculations, the researchers found that 10 percent of their sample of asteroids only cross Mars' orbit, and not Earth's. DeMeo explored other potential causes of asteroid refreshing, calculating the probability of asteroids colliding with each other, as well as the possibility for a phenomenon called "spin-up," in which energy from the sun causes the asteroid to rotate faster and faster, possibly disrupting its surface. From her calculations, DeMeo found no conclusive evidence that either event would significantly refresh asteroids, suggesting that "Mars is the only game in town," Binzel says.

Although 10 percent of 60 asteroids may not seem like a significant number, DeMeo notes that given Mars' small size, the fact that the planet may have an effect on one out of 10 asteroids is noteworthy. "Mars is more powerful than we expected," she says.

The researchers add that now that Mars has been proven to refresh asteroids, other planets, such as Venus, may have similar capabilities — particularly since Venus is closer in mass to Earth.

"You think about these asteroids going around the sun doing their own thing, but there's really a lot more going on in their histories," says DeMeo, who is now a postdoc at Harvard University. "This gives you a dynamic idea of the lives of asteroids." ### This work was supported by the National Science Foundation.

Written by Jennifer Chu, MIT News Office


ELSE PRESS RELEASES FROM THIS DATE:

Researchers classify urban residential desert landscapes

2013-11-19
Researchers classify urban residential desert landscapes Information helps residents and planners create landscape budgets, manage water resources LAS CRUCES, NM--A new study contains valuable information for homeowners and horticulturalists ...

New bale unroller design deemed effective

2013-11-19
New bale unroller design deemed effective Offset round-bale unroller makes mulching more efficient in organic mulch trials LEXINGTON, KY--John Wilhoit and Timothy Coolong from the University of Kentucky have introduced a new technology that ...

First-ever survey of Do-It-Yourself Biology community challenges myths

2013-11-19
First-ever survey of Do-It-Yourself Biology community challenges myths Poll finds 'DIYers' working at community labs on benign, educational experiments WASHINGTON—As the Do-It-Yourself Biology ...

Study: Odds of rehospitalization of cognitively impaired varies by discharge destination

2013-11-19
Study: Odds of rehospitalization of cognitively impaired varies by discharge destination INDIANAPOLIS -- Cognitively impaired older adults released from the hospital are less likely to be rehospitalized within 30 days if they go to a nursing home than if they return ...

Phthalate exposure linked to preterm birth

2013-11-19
Phthalate exposure linked to preterm birth ANN ARBOR—The odds of preterm birth for women exposed to a commonly used class of chemicals known as phthalates are increased significantly, according to a new study from the University of Michigan School of Public ...

Non-specialist health workers play important role in improving mental health in developing countries

2013-11-19
Non-specialist health workers play important role in improving mental health in developing countries New research shows benefits for people with depression, anxiety, dementia, maternal depression, post traumatic stress disorder and alcohol abuse Non-specialist ...

Corticosteroid added to standard treatment improves eyesight in patients with sudden vision loss

2013-11-19
Corticosteroid added to standard treatment improves eyesight in patients with sudden vision loss According to study published in Restorative Neurology and Neuroscience Amsterdam, NL, November 19, 2013 – Nonarteritic anterior ischemic optic neuropathy (NAION) is one of the ...

Blood test accurately diagnoses concussion and predicts long term cognitive disability

2013-11-19
Blood test accurately diagnoses concussion and predicts long term cognitive disability Penn medicine researchers discover that high levels of a protein in blood after traumatic brain injury correlate with brain tissue damage PHILADELPHIA ...

'GUMBOS' promise new drugs and electronics: American Chemical Society Prized Science video

2013-11-19
'GUMBOS' promise new drugs and electronics: American Chemical Society Prized Science video A group of nanoparticles called "GUMBOS" is as varied as their culinary namesake implies, with a wide range of potential applications from cancer therapy to sensors. ...

Smartphone apps lack proven strategies to help smokers quit

2013-11-19
Smartphone apps lack proven strategies to help smokers quit WASHINGTON, DC (November 19, 2013)—An estimated 11 million smokers in the United States own a smartphone and increasingly they're turning to apps ...

LAST 30 PRESS RELEASES:

Osteoporosis treatment benefits people older than 80

Consuming more protein may protect patients taking anti-obesity drug from muscle loss

Thyroid treatment may improve gut health in people with hypothyroidism

Combination of obesity medication tirzepatide and menopause hormone therapy fuels weight loss

High blood sugar may have a negative impact on men’s sexual health

Emotional health of parents tied to well-being of children with growth hormone deficiency

Oxytocin may reduce mood changes in women with disrupted sleep

Mouse study finds tirzepatide slowed obesity-associated breast cancer growth

CMD-OPT model enables the discovery of a potent and selective RIPK2 inhibitor as preclinical candidate for the treatment of acute liver injury

Melatonin receptor 1a alleviates sleep fragmentation-aggravated testicular injury in T2DM by suppression of TAB1/TAK1 complex through FGFR1

Single-cell RNA sequencing reveals Shen-Bai-Jie-Du decoction retards colorectal tumorigenesis by regulating the TMEM131–TNF signaling pathway-mediated differentiation of immunosuppressive dendritic ce

Acta Pharmaceutica Sinica B Volume 15, Issue 7 Publishes

New research expands laser technology

Targeted radiation offers promise in patients with metastasized small cell lung cancer to the brain

A high clinically translatable strategy to anti-aging using hyaluronic acid and silk fibroin co-crosslinked hydrogels as dermal regenerative fillers

Mount Sinai researchers uncover differences in how males and females change their mind when reflecting on past mistakes

CTE and normal aging are difficult to distinguish, new study finds

Molecular arms race: How the genome defends itself against internal enemies

Tiny chip speeds up antibody mapping for faster vaccine design

KTU experts reveal why cultural heritage is important for community unity

More misfolded proteins than previously known may contribute to Alzheimer’s and dementia

“Too much going on”: Autistic adults overwhelmed by non-verbal social cues

What’s driving America’s deep freezes in a warming world?

A key role of brain protein in learning and memory is deciphered by scientists

Heart attacks don’t follow a Hollywood script

Erin M. Schuman wins 2026 Nakasone Award for discovery on neural synapse function and change during formation of memories

Global ocean analysis could replace costly in-situ sound speed profiles in seafloor positioning, study finds

Power in numbers: Small group professional coaching reduces rates of physician burnout by nearly 30%

Carbon capture, utilization, and storage: A comprehensive review of CCUS-EOR

New high-temperature stable dispersed particle gel for enhanced profile control in CCUS applications

[Press-News.org] Asteroids' close encounters with Mars