The aorta is the body's largest artery. It carries oxygen-rich blood from the heart to the rest of the body. The inner lining of any artery can develop fatty plaques that harden. This process is called atherosclerosis. When the lining of an artery is affected by atherosclerosis, calcium can deposit in the areas of atherosclerosis.
Seeing calcification in the aorta most likely means there is some atherosclerosis in your largest artery. Such calcifications are often seen in people as they get older. The calcifications themselves are not a risk to you. However, finding evidence of atherosclerosis in your aorta probably means you have atherosclerosis in the arteries of your heart and brain. This increases your risk for heart attack and stroke.
Similar to other cardiovascular risk factors, these calcifications are a sign that you should be diligent about adopting "heart-healthy" habits. This is especially true if you smoke or have diabetes, an abnormal cholesterol profile or high blood pressure. At your next appointment with your doctor, ask if there is anything else you can do to lower your risk of heart attack and stroke.
By the way, you may see advertisements for "chelation" (kee-LAY-shun) treatments. They supposedly remove calcium deposits from the lining of arteries. There is no proven value from such treatments.